Arthur C Clarke.

The City and the Stars.

Preface.

For the benefit of those who have read my first novel, against the fall of night, and will recognize some of the material in the present work, a few words of explanation are in order. Against the fall of night was begun in 1937 and, after four or five drafts, was completed in 1946, though for various reasons beyond the author's control book publication was delayed until some years later. Although this work was well received, it had most of the defects of a first novel, and my initial dissatisfaction with it increased steadily over the years. Moreover, the progress of science during the two decades since the story was first conceived made many of the original ideas naive, and opened up vistas and possibilities quite unimagined when the book was originally planned. In particular, certain developments in information theory suggested revolutions in the human way of life even more profound than those which atomic energy is already introducing, and i wished to incorporate these into the book i had attempted, but so far failed, to write. A sea voyage from England to Australia gave an opportunity of getting to grips with the uncompleted job, which was finished just before i set out to the great barrier reef. The knowledge that i was to spend some months diving among sharks of doubtful docility was an additional spur to action. It may or may not be true, as doctor Johnson stated, that nothing settles a man's mind so much as the knowledge that he will be hanged in the morning, but for my part i can testify that the thought of not returning from the reef was the main reason why the book was completed at that particular time, and the ghost that had haunted me for almost twenty years was finally exorcised. About a quarter of the present work appeared in against the fall of night; it is my belief, however, that even those who read the earlier book will find that this is virtually a new novel. If not, at least i hope they will grant an author the right to have second thoughts. I promise them that this is my last word on the immortal city of Diaspora, in the long twilight of earth.

Arthur c. Clarke London, September, 1954 - S.D. Himalayan - Sydney, march, 1955 Like a glowing jewel, the city lay upon the breast of the desert. Once it had known change and alteration, but now time pa.s.sed it by. Night and day fled across the desert's face, but in the streets of Diaspora it was always afternoon, and darkness never came. The long winter nights might dust the desert with frost, as the last moisture left in the thin air of earth congealed-but the city knew neither heat nor cold. It had no contact with the outer world; it was a universe itself. Men had built cities before, but never a city such as this. Some had lasted for centuries, some for millenniums, before time had swept away even their names. Diaspora alone had challenged eternity, defending itself and all it sheltered against the slow attrition of the ages, the ravages of decay, and the corruption of rust. Since the city was built, the oceans of earth had pa.s.sed away and the desert had encompa.s.sed all the globe. The last mountains had been ground to dust by the winds and the rain, and the world was too weary to bring forth more. The city did not care; earth itself could crumble and Diaspora would still protect the children of its makers, bearing them and their treasures safely down the stream of time. They had forgotten much, but they did not know it. They were as perfectly fitted to their environment as it was to them -for both had been designed together. What was beyond the walls of the city was no concern of theirs; it was something that had been shut out of their minds. Diaspora was all that existed, all that they needed, all that they could imagine. It mattered nothing to them that man had once possessed the stars. Yet sometimes the ancient myths rose up to haunt them, and they stirred uneasily as they remembered the legends of the empire, when Diaspora was young and drew its lifeblood from the commerce of many suns. They did not wish to bring back the old days, for they were content in their eternal autumn. The glories of the empire belonged to the past, and could remain there-for they remembered how the empire had met its end, and at the thought of the invaders the chill of s.p.a.ce itself came seeping into their bones. Then they would turn once more to the life and warmth of the city, to the long golden age whose beginning was already lost and whose end was yet more distant. Other men had dreamed of such an age, but they alone had achieved it. They had lived in the same city, had walked the same miraculously unchanging streets, while more than a billion years had worn away.

One.

It had taken them many hours to fight their way out of the cave of the white worms. Even now, they could not be sure that some of the pallid monsters were not pursuing them -and the power of their weapons was almost exhausted. Ahead, the floating arrow of light that had been their mysterious guide through the labyrinths of the crystal mountain still beckoned them on. They had no choice but to follow it, though as it had done so many times before it might lead them into yet more frightful dangers. Alvin glanced back to see if all his companions were still with him. Alystra was close behind, carrying the sphere of cold but ever-burning light that had revealed such horrors and such beauty since their adventure had begun. The pale white radiance flooded the narrow corridor and splashed from the glittering walls; while its power lasted, they could see where they were going and could detect the presence of any visible dangers. But the greatest dangers in these caves, Alvin knew too well, were not the visible ones at all. Behind Alystra, struggling with the weight of their projectors, came brilliant and lorans. Alvin wondered briefly why those projectors were so heavy, since it would have been such a simple matter to provide them with gravity neutralizers. He was always thinking of points like this, even in the midst of the most desperate adventures. When such thoughts crossed his mind, it seemed as if the structure of reality trembled for an instant, and that behind the world of the senses he caught a glimpse of another and totally different universe.... The corridor ended in a blank wall. Had the arrow betrayed them again? No-even as they approached, the rock began to crumble into dust. Through the wall pierced a spinning metal spear, which broadened rapidly into a giant screw. Alvin and his friends moved back, waiting for the machine to force its way into the cave. With a deafening screech of metal upon rock-which surely must echo through all the recesses of the mountain, and waken all its nightmare brood!-the sub terrene smashed through the wall and came to rest beside them. A ma.s.sive door opened, and callistron appeared, shouting to them to hurry. ("Why callistron?" wondered Alvin. "What's he doing here?") a moment later they were in safety, and the machine lurched forward as it began its journey through the depths of the earth.

The adventure was over. Soon, as always happened, they would be home, and all the wonder, the terror, and the excitement would be behind them. They were tired and content. Alvin could tell from the tilt of the floor that the sub terrene was heading down into the earth. Presumably callistron knew what he was doing, and this was the way that led to home. Yet it seemed a pity... "Callistron," he said suddenly, "why don't we go upward? No one knows what the crystal mountain really looks like. How wonderful it would be to come out somewhere on its slopes, to see the sky and all the land around it. We've been underground long enough." even as he said these words, he somehow knew that they were wrong. Alystra gave a strangled scream, the interior of the sub terrene wavered like an image seen through water, and behind and beyond the metal walls that surrounded him Alvin once more glimpsed that other universe. The two worlds seemed in conflict, first one and then the other predominating. Then quite suddenly, it was all over. There was a snapping, rending sensation-and the dream had ended. Alvin was back in Diaspora, in his own familiar room, floating a foot or two above the floor as the gravity field protected him from the bruising contact of brute matter.

He was himself again. This was reality-and he knew exactly what would happen next. Alystra was the first to appear. She was more upset than annoyed, for she was very much in love with Alvin. "Oh, Alvin!" she lamented as she looked down at him from the wall in which she had apparently materialized, "it was such an exciting adventure! Why did you have to spoil it?" "I'm sorry. I didn't intend to -- I just thought it would be a good idea..." He was interrupted by the simultaneous arrival of callistron and flora.n.u.s. "Now listen, Alvin," began callistron. "This is the third time you've interrupted a saga. You broke the sequence yesterday by wanting to climb out of the valley of rainbows. And the day before you upset everything by trying to get back to the origin in that time track we were exploring. If you won't keep the rules, you'll have to go by yourself." he vanished in high dudgeon taking flora.n.u.s with him. Narillian never appeared at all; he was probably too fed up with the whole affair. Only the image of alystra was left, looking sadly down at alvin. Alvin tilted the gravity field, rose to his feet, and walked toward the table he had materialized. A bowl of exotic fruit appeared upon it-not the food he had intended, for in his confusion his thoughts had wandered: not wishing to revealhis error, he picked up the least dangerous-looking of the fruits and started to suck it cautiously. "Well," said alystra at last, "what are you going to do?" "i can't help it," he said a little sulkily. "I think the rules are stupid. Besides, how can i remember them when i'm living a saga? I just behave in the way that seems natural. Didn't you want to look at the mountain?" alystra's eyes widened with horror. "That would have meant going outside!" she gasped. Alvin knew that it was useless to argue further. Here was the barrier that sundered him from all the people of his world, and which might doom him to a life of frustration. He was always wanting to go outside, both in reality and in dream. Yet to everyone in diaspar, "outside" was a nightmare that they could not face. They would never talk about it if it could be avoided; it was something unclean and evil. Not even jeserac his tutor, would tell him why. Alystra was still watching him with puzzled but tender eyes. "You're unhappy, alvin," she said. ' No one should be unhappy in diaspar. Let me come over and talk to you." ungallantly, alvin shook his head. He knew where that would lead and at the moment he wanted to be alone. Doubly disappointed, alystra faded from view. In a city of ten million human beings, thought alvin, there was no one to whom he could really talk. Eriston and etania were fond of him in their way, but now that their term of guardianship was ending, they were happy enough to leave him to shape his own amus.e.m.e.nts and his own life. In the last few years, as his divergence from the standard pattern became more and more obvious, he had often felt his parents' resentment. Not with him-that perhaps, was something he could have faced and fought-but with the sheer bad luck that had chosen them from all the city's millions, to meet him when he walked out of the hall of creation twenty years ago. Twenty years. He could remember the first moment, and the first words he had ever heard: "welcome, alvin. I am eriston, your appointed father. This is etania, your mother." the words had meant nothing then, but his mind had recorded them with flawless accuracy. He remembered how he had looked down at his body; it was an inch or two taller now, but had scarcely altered since the moment of his birth. He had come almost fully grown into the world, and would have changed little save in height when it was time to leave it a thousand years hence. Before that first memory, there was nothing. One day, perhaps, that nothingness would come again, but that was a thought too remote to touch his emotions in any way. He turned his mind once more toward the mystery of his birth. It did not seem strange to alvin that he might be created, in a single moment of time, by the powers and forces that materialized all the other objects of his everyday life. No; that was not the mystery. The enigma he had never been able to solve, and which no one would ever explain to him, was his uniqueness. Unique. It was a strange, sad word-and a strange, sad thing to be. When it was applied to him-as he had often heard it done when no one thought he was listening-it seemed to possess ominous undertones that threatened more than his own happiness. His parents, his tutor, everyone he knew, had tried to protect him from the truth, as if anxious to preserve the innocence of his long childhood. The pretense must soon be ended; in a few days he would be a full citizen of diaspar, and nothing could be withheld from him that he wished to know. Why, for example, did he not fit into the sagas? Of all the thousands of forms of recreation in the city, these were the most popular. When you entered a saga, you were not merely a pa.s.sive observer, as in the crude entertainments of primitive times which alvin had sometimes sampled. You were an active partic.i.p.ant and possessed-or seemed to possess-free will. The events and scenes which were the raw material of your adventures might have been prepared beforehand by forgotten artists, but there was enough flexibility to allow for wide variation. You could go into these phantom worlds with your friends, seeking the excitement that did not exist in diaspar-and as long as the dream lasted there was no way in which it could be distinguished from reality. Indeed, who could be certain that diaspar itself was not the dream? No one could ever exhaust all the sagas that had been conceived and recorded since the city began. They played upon all the emotions and were of infinitely varying subtlety. Some-those popular among the very young-were uncomplicated dramas of adventure and discovery. Others were purely explorations of psychological states, while others again were exercises in logic or mathematics which could provide the keenest of delights to more sophisticated minds. Yet though the sagas seemed to satisfy his companions, they left alvin with a feeling of incompleteness. For all their color and excitement, their varying locales and themes, there was something missing. The sagas, he decided, never really got anywhere. They were always painted on such a narrow canvas. There were no great vistas, none of the rolling landscapes for which his soul craved. Above all, there was never a hint of the immensity in which the exploits of ancient man had really taken place -the luminous void between the stars and planets. The artists who had planned the sagas had been infected by the same strange phobia that ruled all the citizens of diaspar. Even their vicarious adventures must take place cozily indoors, in subterranean caverns, or in neat little valleys surrounded by mountains that shut out all the rest of the world. There was only one explanation. Far back in time, perhaps before diaspar was founded, something had happened that had not only destroyed man's curiosity and ambition, but had sent him homeward from the stars to cower for shelter in the tiny closed world of earth's last city. He had renounced the universe and returned to the artificial womb of diaspar. The flaming, invincible urge that had once driven him over the galaxy, and to the islands of mist beyond, had altogether died. No ships had entered the solar system for countless aeons; out there among the stars the descendants of man might still be building empires and wrecking suns-earth neither knew nor cared. Earth did not. But alvin did.

Two.

The room was dark save for one glowing wall, upon which the tides of color ebbed and flowed as alvin wrestled with his dreams. Part of the pattern satisfied him; he had fallen in love with the soaring lines of the mountains as they leaped out of the sea. There was a power and pride about those ascending curves; he had studied them for a long time, and then fed them into the memory unit of the visualizes, where they would be preserved while he experimented with the rest of the picture. Yet something was eluding him, though what it was he did not know. Again and again he had tried to fill in the blank s.p.a.ces, while the instrument read the shifting patterns in his mind and materialized them upon the wall. It was no good. The lines were blurred and uncertain, the colors muddy and dull. If the artist did not know his goal, even the most miraculous of tools could not find it for him. Alvin canceled his unsatisfactory scribblings and stared morosely at the three-quarters-empty rectangle he had been trying to fill with beauty. On a sudden impulse, he doubled the size of the existing design and shifted it to the center of the frame. No-that was a lazy way out, and the balance was all wrong. Worse still, the change of scale had revealed the defects in his construction, the lack of certainty in those atfirst-sight confident lines. He would have to start all over again. "Total erasure," he ordered the machine. The blue of the sea faded; the mountains dissolved like mist, until only the blank wall remained. They were as if they had never beenas if they were lost in the limbo that had taken all earth's seas and mountains ages before alvin was born. The light came flooding back into the room and the luminous rectangle upon which alvin had projected his dreams merged into its surroundings, to become one with the other walls. But were they walls? To anyone who had never seen such a place before, this was a very peculiar room indeed. It was utterly featureless and completely devoid of furniture, so that it seemed as if alvin stood at the center of a sphere. No visible dividing lines separated walls from floor or ceiling. There was nothing on which the eye could focus; the s.p.a.ce enclosing alvin might have been ten feet or ten miles across, for all that the sense of vision could have told. It would have been hard to resist the temptation to walk forward, hands outstretched, to discover the physical limits of this extraordinary place. Yet such rooms had been "home" to most of the human race for the greater part of its history. Alvin had only to frame the appropriate thought, and the walls would become windows opening upon any part of the city he chose. Another wish, and machines which he had never seen would fill the chamber with the projected images of any articles of furniture he might need. Whether they were "real" or not was a problem that had bothered few men for the last billion years. Certainly they were no less real than that other impostor, solid matter, and when they were no longer required they could be returned to the phantom world of the city's memory banks. Like everything else in diaspar, they would never wear out-and they would never change, unless their stored patterns were canceled by a deliberate act of will. Alvin had partly reconstructed his room when a persistent, bell-like chime sounded in his ear. He mentally framed the admission signal, and the wall upon which he had just been painting dissolved once more. As he bad expected, there stood his parents, with jeserac a little behind them. The presence of his tutor meant that this was no ordinary family reunion -but he knew that already.... The illusion was perfect, and it was not lost when eriston spoke. In reality, as alvin was well aware, eriston etania, and jeserac were all miles apart, for the builders of the city had conquered s.p.a.ce as completely as they had subjugated time. Alvin was not even certain where his parents lived. Among the mult.i.tudinous spires and intricate labyrinths of diaspar, for they had both moved since he had last been physically in their presence.

Alvin," began eriston, "it is just twenty years since your mother and i first met you. You know what that means. Our guardianship is now ended, and you are free to do as you please." there was a trace--but merely a trace--of sadness in brixton's voice. There was considerably more relief, as if eriston was glad that a state of affairs that had existed for some time in fact now had legal recognition. Alvin had antic.i.p.ated his freedom by a good many years. "I understand," he answered. "I thank you for watching over me, and i will remember you in all my lives." that was the formal response; he had heard it so often that all meaning had been leached away from it-it was merely a pattern of sounds with no particular significance. Yet "all my lives" was a strange expression, when one stopped to consider it. He knew vaguely what it meant; now the time had come for him to know exactly. There were many things in diaspar which he did not understand, and which he would have to learn in the centuries that lay ahead of him. For a moment it seemed as if etania wished to speak. She raised one hand, disturbing the iridescent gossamer of her gown, then let it fall back to her side. Then she turned helplessly to jeserac, and for the first time alvin realized that his parents were worried. His memory swiftly scanned the events of the past few weeks. No, there was nothing in his recent life that could have caused this faint uncertainty, this air of mild alarm that seemed to surround both eriston and etania. Jeserac, however, appeared to be in command of the situation. He gave an inquiring look at eriston and etania, satisfied himself that they had nothing more to say, and launched forth on the dissertation he had waited many years to make. "Alvin," he began, "for twenty years you have been my pupil, and i have done my best to teach you the ways of the city, and to lead you to the heritage which is yours. You have asked me many questions, and not all of them have i been able to answer. Some things you were not ready to learn, and some i did not know myself. Now your infancy is over, though your childhood is scarcely begun. It is still my duty to guide you, if you need my help. In two hundred years, alvin , you may begin to know something of this city and a little of its history. Even i, who am nearing the end of this life, have seen less than a quarter of diaspar, and perhaps less than a thousandth of its treasures." there was nothing so far that alvin did not know, but there was no way of hurrying jeserac. The old man looked steadfastly at him across the gulf of centuries, his words weighed down with the uncomputable wisdom acquired during a long lifetime's contact with men and machines. "Tell me, alvin," he said, "have you ever asked yourself where you were before you were born-before you found yourself facing etania and eriston at the hall of creation?" "i a.s.sumed i was nowhere-that i was nothing but a pattern in the mind of the city, waiting to be created-like this." a low couch glimmered and thickened into reality beside alvin. He sat down upon it and waited for jeserac to continue.

"You are correct, of course," came the reply. "But that is merely part of the answer-and a very small part indeed. Until now, you have met only children of your own age, and they have been ignorant of the truth. Soon they will remember, but you will not, so we must prepare you to face the facts. For over a billion years, alvin, the human race has lived in this city. Since the galactic empire fell, and the invaders. Went back to the stars, this has been our world. Outside the walls of diaspar, there is nothing except the desert of which our legends speak. "We know little about our primitive ancestors, except that they were very short-lived beings and that, strange though it seems, they could reproduce themselves without the aid of memory units or matter organizers. In a complex and apparently uncontrollable process, the key patterns of each human being were preserved in microscopic cell structures actually created inside the body. If you are interested, the biologists can tell you more about it, but the method is of no great importance since it was abandoned at the dawn of history. "A human being, like any other object, is defined by its structure-its pattern. The pattern of a man, and still more the pattern which specifies a man's mind, is incredibly complex. Yet nature was able to pack that pattern into a tiny cell, too small for the eye to see. "What nature can do, man can do also, in his own way." we do not know how long the task took. A million years, perhaps-but what is that? In the end our ancestors learned how to a.n.a.lyze and store the information that would define any specific human being-and to use that information to re-create the original, as you have just created that couch. "I know that such things interest you, alvin, but i cannot tell you exactly how it is done. The way in which information is stored is of no importance; all that matters is the information itself. It may be in the form of written words on paper, n of varying magnetic fields, or patterns of electric charge. Men a have used all these methods of storage, and many others. Suffice to say that long ago they were able to store themselvesor, to be more precise, the disembodied patterns from which they could be called back into existence. "So much, you already know. This is the way our ancestors gave us virtual immortality, yet avoided the problems raised by the abolition of death. A thousand years in one body is long enough for any man; at the end of that time, his mind is clogged with memories, and he asks only for rest-or a new beginning. In a little while, alvin, i shall prepare to leave this life. I shall go back through my memories, editing them and canceling those i do not wish to keep. Then i shall walk into the hall of creation, but through a door which you have never seen. This old body will cease to exist, and so will consciousness itself. Nothing will be left of jeserac but a galaxy of electrons frozen in the heart of a crystal. "I shall sleep, alvin, and without dreams. Then one day, perhaps a hundred thousand years from now, i shall find myself in a new body, meeting those who have been chosen to be my guardians. They will look after me as eriston and etania have guided you, for at first i will know nothing of diaspar and will have no memories of what i was before. Those memories will slowly return, at the end of my infancy, and i will build upon them as i move forward into my new cycle of existence. "That is the pattern of our lives, alvin. We have all been here many, many times before, though as the intervals of nonexistence vary according to apparently random laws this present population will never repeat itself again. The new jeserac will have new and different friends and interests, but the old jeserac-as much of him as i wish to save-will still exist. "That is not all. At any moment, alvin, only a hundredth of the citizens of diaspar live and walk its streets. The vast majority slumber in the memory banks, waiting for the signal that will call them forth onto the stage of existence once again. So we have continuity, yet change-immortality, but not stagnation. I know what you are wondering, alvin. You want to know when you will recall the memories of your earlier lives, as your companions are already doing. "There are no such memories, for you are unique. We have tried to keep this knowledge from you as long as we could, so that no shadow should lie across your childhood-though i think you must have guessed part of the truth already. We did not suspect it ourselves until five years ago, but now there is no doubt. "You alvin, are something that has happened in diaspar a handful of times since the founding of the city. Periys you have been lying dormant in the memory banks through all the ages-or perhaps you were created only twenty years ago by some random permutation. You may have been planned in the beginning by the designers of the city, or you may be a purposeless accident of our own time. "We do not know. All that we do know is this: you, alvin, alone of the human race, have never lived before. In literal truth, you are the first child to be born on earth for at least ten million years."

Three.

When jeserac and his parents had faded from view, alvin lay for a long time trying to hold his mind empty of thought. He closed his room around him, so that no one could interrupt his trance.

He was not sleeping; sleep was something he had never experienced, for that, belonged to a world of night and day, and here there was only day. This was the nearest he could come to that forgotten state, and though it was not really essential to him he knew that it would help compose his mind.

He had learned little new; almost everything that jeserac had told him he had already guessed. But it was one thing to have guessed it, another to have had that guess confirmed beyond possibility of refutation.

How would it affect his life, if at all? He could not be sure, and uncertainty was a novel sensation to alvin. Perhaps it would make no difference whatsoever; if he did not adjust completely to diaspar in this life, he would do so in the next -or the next.

Even as he framed the thought, alvin's mind rejected it. Diaspar might be sufficient for the rest of humanity, but it was not enough for him. He did not doubt that one could spend a thousand lifetimes without exhausting all its wonders, or sampling all the permutations of experience it could provide. These things he could do-but if he could not do more, he would never be content.

There was only one problem to be faced. What more was there to do?

The unanswered question jolted him out of his reverie. He could not stay here while he was in this restless mood, and there was only one place in the city where he could find some peace of mind.

The wall flickered partially out of existence as he stepped through to the corridor, and its polarized molecules resisted his pa.s.sage like a feeble wind blowing against his face. There were, many ways in which he could be carried effortlessly to his goal, but he preferred to walk. His room was almost at the main city level, and a short pa.s.sage brought him out onto a spiral ramp which led down to the street. He ignored the moving way, and kept to the narrow sidewalk-an eccentric thing to do, since he had several miles to travel. But alvin liked the exercise, for it soothed his mind. Besides, there was so much to see that it seemed a pity to race past the latest marvels of diaspar when you had eternity ahead of you. It was the custom of the city's artists-and everyone in diaspar was an artist at some time or another-to display their current productions along the side of the moving ways, so that the pa.s.sers-by could admire their work. In this manner, it was usually only a few days before the entire population had critically examined any noteworthy creation, and also expressed its views upon it. The resulting verdict, recorded automatically by opinion-sampling devices which no one had ever been able to suborn or deceive and there had been enough attempts-decided the fate of the masterpiece. If there was a sufficiently affirmative vote, its matrix would go into the memory of the city so that anyone who wished, at any future date, could possess a reproduction utterly indistinguishable from the original. The less successful pieces went the way of all such works. They were either dissolved back into their original elements or ended in the homes of the artists' friends. Alvin saw only one object d'art on his journey that had any appeal to him. It was a creation of pure light, vaguely reminiscent of an unfolding flower. Slowly growing from a minute core of color, it would expand into complex spirals and curtains, then suddenly collapse and begin the cycle over again. Yet not precisely, for no two cycles were identical. Though alvin watched through a score of pulsations, each time there were subtle and indefinable differences, even though the basic pattern remained the same. He knew why he liked this piece of intangible sculpture. Its expanding rhythm gave an impression of s.p.a.ce -even of escape. For that reason, it would probably not appeal to many of alvin's compatriots. He made a note of the artist's name and decided to call him at the earliest opportunity. All the roads both moving and stationary, came to an end when they reached the park that was the green heart of the city. Here, in a circular s.p.a.ce over three miles across, was a memory of what earth had been in the days before the desert swallowed all but diaspar. First there was a wide belt of gra.s.s, then low trees which grew thicker and thicker as one walked forward beneath their shade. At the same time the ground sloped gently downward so that when at last one emerged from the narrow forest all sign of the city had vanished, hidden by the screen of trees. The wide stream that lay ahead of alvin was called, simply, the river. It possessed, and it needed, no other name. At intervals it was spanned by narrow bridges, and it flowed around the park in a complete, closed circle, broken by occasional lagoons. That a swiftly moving river could return upon itself after a course of less than six miles had never struck alvin as at all unusual; indeed, he would not have thought twice about the matter if at some point in its circuit the river had flowed uphill. There were far stranger things than this in diaspar.

A dozen young people were swimming in one of the little lagoons, and alvin paused to watch them. He knew most of them by sight, if not by name, and for a moment was tempted to join in their play. Then the secret he was bearing decided him against it, and he contented himself with the role of spectator.

Physically, there was no way of telling which of these young citizens had walked out of the hall of creation this year and which had lived in diaspar as long as alvin. Though there were considerable variations in height and weight, they had no correlation with age. People were simply born that way, and although on the average the taller the person, the greater the age, this was not a reliable rule to apply unless one was dealing in centuries.

The face was a safer guide. Some of the newborn were taller than alvin, but they had a look of immaturity, an expression of wondering surprise at the world in which they now found themselves that revealed them at once. It was strange to think that, slumbering untapped in their minds, were infinite vistas of lives that they would soon remember. Alvin envied them, yet he was not sure if he should. One's first existence was a precious gift which would never be repeated. It was wonderful to view life for the very first time, as in the freshness of the dawn. If only there were others like him, with whom he could share his thoughts and feelingst Yet physically he was cast in precisely the same mold as those children playing in the water. The human body had changed not at all in the billion years since the building of diaspar, since the basic design had been eternally frozen in the memory banks of the city. It had changed, however, a good deal from its original primitive form, though most of the alterations were internal and not visible to the eye. Man had rebuilt himself many times in his long history, in the effort to abolish those ills to which the flesh was once heir.

Such unnecessary appurtenances as nails and teeth had vanished. Hair was confined to the head; not a trace was left on the body. The feature that would most have surprised a man of the dawn ages was, perhaps, the disappearance of the navel. Its inexplicable absence would have given him much food for thought, and at first sight he would also have been baffled by the problem of distinguishing male from female. He might even have been tempted to a.s.sume that there was no longer any difference, which would have been a grave error. In the appropriate circ.u.mstances, there was no doubt about the masculinity of any male in iaspar. It was merely that his equipment was now more neatly packaged when not required; internal stowage had vastly improved upon nature's original inelegant and indeed downright hazardous arrangements.

It was true that that reproduction was no longer the concern of the body, being far too important a matter to be left to games of chance played with chromosomes as dice. Yet, though conception and birth were not even memories, sea remained. Even in ancient times, not one-hundredth part of s.e.xual activity had been concerned with reproduction. The disappearance of that mere one per cent had changed the pattern of human society and the meaning of such words as "father" and "mother"-but desire remained, though now its satisfaction had no profounder aim than that of any of the other pleasures of the senses. Alvin left his playful contemporaries and continued on toward the center of the park. There were faintly marked paths here, crossing and crisscrossing through low shrubbery and occasionally diving into narrow ravines between great lichencovered boulders. Once he came across a small polyhedral machine, no larger than a man's head, floating among the branches of a tree. No one knew how many varieties of robot there were in diaspar; they kept out of the way and minded their business so effectively that it was quite unusual to see one.

Presently the ground began to rise again; alvin was approaching the little hill that was at the exact center of the park, and therefore of the city itself. There were fewer obstacles and detours, and he had a clear view to the summit of the hill and the simple building that surmounted it. He was a little out of breath by the time he had reached his goal, and was glad to rest against one of the rose-pink columns and to look back over the way he had come.

There are some forms of architecture that can never change because they have reached perfection. The tomb of yarlan zey might have been designed by the temple builders of the first civilizations man had ever known, though they would have found it impossible to imagine of what material it was made. The roof was open to the sky, and the single chamber was paved with great slabs which only at first sight resembled natural stone. For geological ages human feet had crossed and recrossed that floor and left no trace upon its inconceivably stubborn material.

The creator of the great park-the builder, some said, of diaspar itself-sat with slightly downcast eyes, as if examining the plans spread across his knees. His face wore that curiously elusive expression that had baffled the world for so many generations. Some had dismissed it as no more than an idle whim of the artist's, but to others it seemed that yarlan zey was smiling at some secret jest. The whole building was an enigma, for nothing concerning it could be traced in the historical records of the city. Alvin was not even sure what the word "tomb" meant; jeserac could probably tell him, because he was fond of collecting obsolete words and sprinkling his conversation with them, to the confusion of his listeners.

From this central vantage point, alvin could look clear across the park, above the screening trees, and out to the city itself. The nearest buildings were almost two miles away, and formed a low belt completely surrounding the park. Beyond them, rank after rank in ascending height, were the towers and terraces that made up the main bulk of the city. They stretched for mile upon mile, slowly climbing up the sky, becoming ever more complex and monumentally impressive. Diaspar had been planned as an ent.i.ty; it was a single mighty machine. Yet though its outward appearance was almost overwhelming in its complexity, it merely hinted at the hidden marvels of technology, without which all these great buildings would be lifeless sepulchers. Alvin stared out toward the limits of his world. Twenty miles away, their details lost in distance, were the outer ramparts of the city, upon which seemed to rest the roof of the sky. There was nothing beyond them-nothing at all except the aching emptiness of the desert in which a man would soon go mad. Then why did that emptiness call to him, as it called to no one else whom he had ever met? Alvin did not know. He stared out across the colored spires and battlements that now enclosed the whole dominion of mankind, as if seeking an answer to his question. He did nol find it. But at that moment, as his heart yearned for the unattainable, he made his decision. He knew now what he was going to do with life.

Four.

Jeserac was not very helpful, though he was not as uncooperative as alvin had half expected. He had been asked such questions before in his long career as mentor, and did not believe that even a unique like alvin could produce many surprises or set him problems which he could not solve. It was true that alvin was beginning to show certain minor eccentricities of behavior, which might eventually need correction. He did not join as fully as he should in the incredibly elaborate social life of the city or in the fantasy worlds of his companions. He showed no great interest in the higher realms of thought, though at his age that was hardly surprising. More remarkable was his erratic love life; he could not be expected to form any relatively stable partnerships for at least a century, yet the brevity of his affairs was already famous. They were intense while they lasted-but not one of them had lasted for more than a few weeks. Alvin, it seemed, could interest himself thoroughly only in one thing at a time. There were times when he would join wholeheartedly in the erotic games of his companions, or disappear with the partner of his choice for several days. But once the mood had pa.s.sed, there would be long spells when he seemed totally uninterested in what should have been a major occupation at his age. This was probably bad for him, and it was certainly bad for his discarded lovers, who wandered despondently around the city and took an unusually long time to find consolation elsewhere. Alystra, jeserac had noticed, had now arrived at this unhappy stage. It was not that alvin was heartless or inconsiderate. In love, as in everything else, it seemed that he was searching for a goal that diaspar could not provide. None of these characteristics worried jeserac. A unique might be expected to behave in such a manner, and in due course alvin would conform to the general pattern of the city. No single individual, however eccentric or brilliant, could affect the enormous inertia of a society that had remained virtually unchanged for over a billion years. Jeserac did not merely believe in stability; he could conceive of nothing else. "The problem that worries you is a very old one," he told alvin, "but you will be surprised how many people take the world so much for granted that it never bothers them or even crosses their mind. It is true that the human race once occupied an infinitely greater s.p.a.ce than this city. You have seen something of what earth was like before the deserts came and the oceans vanished. Those records you are so fond of projecting are the earliest we possess; they are the only ones that show earth as it was before the invaders came. I do not imagine that many people have ever seen them; those limitless, open s.p.a.ces are something we cannot bear to contemplate. "And even earth, of course, was only a grain of sand in the galactic empire. What the gulfs between the stars must have been like is a nightmare no sane man would try to imagine. Our ancestors crossed them at the dawn of history when they went out to build the empire. They crossed them again for the last time when the invaders drove them back to earth.

"The legend is-and it is only a legend-that we made a pact with the invaders. They could have the universe if they needed it so badly, we would be content with the world on which we were born. "We have kept that pact and forgotten the vain dreams of our childhood as you too will forget them, alvin. The men who built this city, and designed the society that went with it, were lords of mind as well as matter. They put everything that the human race would ever need inside these walls-and then made sure that we would never leave them. Oh, the physical barriers are the least important ones. Perhaps there are routes that lead out of the city, but i do not think you would go along them for very far, even if you found them. And if you succeeded in the attempt, what good would it do? Your body would not last long in the desert, when the city could no longer protect or nourish it." "if there is a route out of the city," said alvin slowly, "then what is there to stop me from leaving?" "that is a foolish question," answered jeserac. "I think you already know the answer." jeserac was right, but not in the way he imagined. Alvin knew-or, rather, he had guessed. His companions had given him the answer, both in their waking life and in the dream adventures he had shared with them. They would never be able to leave diaspar; what jeserac did not know was that the compulsion which ruled their lives had no power over alvin. Whether his uniqueness was due to accident or to an ancient design, he did not know, but this was one of its results. He wondered how many others he had yet to discover. No one ever hurried in diaspar, and this was a rule which even alvin seldom broke. He considered the problem care-fully for several weeks, and spent much time searching the earliest of the city's historical memories. For hours on end he would lie, supported by the impalpable arms of an anti-gravity field, while the hypnone projector opened his mind to the past. When the record was finished, the machine would blur and vanish-but still alvin would lie staring into nothing-ness before he came back through the ages to meet reality again. He would see again the endless leagues of blue water, vaster than the land itself, rolling their waves against golden sh.o.r.es. His ears would ring with the boom of breakers stilled these billion years. He would remember the forests and the prairies, and the strange beasts that had once shared the world with man. Very few of these ancient records existed; it was generally accepted, though none knew the reason why, that somewhere between the coming of the invaders and the building of diaspar all memories of primitive times had been lost. So com-plete had been the obliteration that it was hard to believe it could have happened by accident alone. Mankind had lost its past, save for a few chronicles that might be wholly leg-endary. Before diaspar there was simply the dawn ages. In that limbo were merged inextricably together the first men to tame fire and the first to release atomic energy-the first men to build a log canoe and the first to reach the stars. On the far side of this desert of time, they were all neighbors. Alvin had intended to make this trip alone once more, but solitude was not always something that could be arranged in diaspar. He had barely left his room when he encountered alystra, who made no attempt to pretend that her presence was accidental. It had never occurred to alvin that alystra was beautiful, for he had never seen human ugliness. When beauty is universal, it loses its power to move the heart, and only its absence can produce any emotional effect. For a moment alvin was annoyed by the meeting, with its reminder of pa.s.sions that no longer moved him. He was still too young and self-reliant to feel the need for any lasting relationships, and when the time came he might find it hard to make them. Even in his most intimate moments, the barrier of his uniqueness came between him and his lovers. For all his fully formed body, he was still a child and would re-main so for decades yet, while his companions one by one recalled the memories of their past lives and left him far behind. He had seen it happen before, and it made him wary of giving himself unreservedly to any other person. Even alys-tra, who seemed so naive and artless now, would soon be-come a complex of memories and talents beyond his imagination.

His mild annoyance vanished almost at once. There was no reason why alystra should not come with him if she desired. He was not selfish and did not wish to clutch this new experience to his bosom like a miser. Indeed, he might be able to learn much from her reactions. She asked no questions, which was unusual, as the express channel swept them out of the crowded heart of the city. Together they worked their way to the central high-speed section, never bothering to glance at the miracle beneath their feet. An engineer of the ancient world would have gone slowly mad trying to understand how an apparently solid roadway could be fixed at the sides while toward the center it moved at a steadily increasing velocity. But to alvin and alystra, it seemed perfectly natural that types of matter should exist that had the properties of solids in one direction and of liquids in another. Around them the buildings rose higher and higher as if the city was strengthening its bulwarks against the outer world. How strange it would be, thought alvin, if these towering walls became as transparent as gla.s.s, and one could watch the life within. Scattered throughout the s.p.a.ce around him were friends he knew, friends he would one day know, and strangers he would never meet-though there could be very few of these since in the course of his lifetime he would meet almost all the people in diaspar. Most of them would be sitting in their separate rooms, but they would not be alone. They had only to form the wish and they could be, in all but physical fact, in the presence of any other person they chose. They were not bored, for they had access to every thing that had happened in the realms of imagination or reality since the days when the city was built. To men whose minds were thus const.i.tuted, it was a completely satisfying existence. That it was also a wholly futile one, even alvin did not yet comprehend. As alvin and alystra moved outward from the city's heart, the number of people they saw in the streets slowly decreased, and there was no one in sight when they were brought to a smooth halt against a long platform of brightly colored marble. They stepped across the frozen whirlpool of matter where the substance of the moving way flowed back to its origin, and faced a wall pierced with brightly lighted tunnels. Alvin selected one without hesitation and stepped into it, with alystra close behind. The peristaltic field seized them at once and propelled them forward as they lay back luxuriously, watching their surroundings. It no longer seemed possible that they were in a tunnel far underground. The art that had used all of diaspar for its canvas had been busy here, and above them the skies seemed open to the winds of heaven. All around were the spires of the city, gleaming in the sunlight. It was not the city that alvin knew, but the diaspar of a much earlier age. Although most of the great buildings were familiar, there were subtle differences that added to the interest of the scene. Alvin wished he could linger, but he had never found any way of r.e.t.a.r.ding his progress through the tunnel. All too soon they were set gently down in a large elliptical chamber, completely surrounded by windows. Through these they could catch tantalizing glimpses of gardens ablaze with brilliant flowers. There were gardens still in diaspar, but these had existed only in the mind of the artist who conceived them. Certainly there were no such flowers as these in the world today. Alystra was enchanted by their beauty, and was obviously under the impression that this was what alvin had brought her to see. He watched her for a while as she ran gaily from scene to scene, enjoying her delight in each new discovery. There were hundreds of such places in the half-deserted buildings around the periphery of diaspar, kept in perfect order by the hidden powers which watched over them. One day the tide of life might flow this way once more, but until then this ancient garden was a secret which they alone shared. "We've further to go," said alvin at last. "This is only the beginning." he stepped through one of the windows and the illusion was shattered. There was no garden behind the gla.s.s, but a circular pa.s.sageway curving steeply upward. He could still see alystra, a few feet away, though he knew that she could not see him. But she did not hesitate, and a moment later was standing beside him in the pa.s.sage. Beneath their feet the floor began to creep slowly forward, as if eager to lead them to their goal. They walked along it for a few paces, until their speed was so great that further effort would be wasted. The corridor still inclined upward, and in a hundred feet had curved through a complete right angle. But only logic knew this; to all the senses it was as if one was now being hurried along an absolutely level corridor. The fact that they were in reality moving straight up a vertical shaft thousands of feet deep gave them no sense of insecurity, for a failure of the polarizing field was unthinkable. Presently the corridor began to slope "downward" again until once more it had turned through a right angle. The movement of the floor slowed imperceptibly until it came to rest at the end of a long hall lined with mirrors, and alvin knew that there was no hope of hurrying alystra here. It was not merely that some feminine characteristics had survived unchanged since eve; no one could have resisted the fascina-tion of this place. There was nothing like it, as far as alvin knew, in the rest of diaspar. Through some whim of the art-ist, only a few of the mirrors reflected the scene as it really was-and even those, alvin was convinced were constantly changing their position. The rest certainly reflected something, but it was faintly disconcerting to see oneself walking amid ever-changing and quite imaginary surroundings. Sometimes there were people going to and fro in the world behind the mirror, and more than once alvin had seen faces that he recognized. He realized well enough that he had not been looking at any friends he knew in this existence. Through the mind of the unknown artist he had been seeing into the past watching the previous incarnations of people who walked the world today. It saddened him, by reminding him of his own uniqueness, to think that however long he waited before these changing scenes he would never meet any ancient echo of himself. "Do you know where we are?" alvin asked alystra when they had completed the tour of the mirrors. Alystra shook her head. "Somewhere near the edge of the city, i suppose," she answered carelessly. "We seem to have gone a long way, but i've no idea how far." "we're in the tower of loranne," replied alvin. "This is one of the highest points in diaspar. Come-i'll show you." he caught alystra's hand and led her out of the hall. There were no exits visible to the eye, but at various points the pattern on the floor indicated side corridors. As one approached the mirrors at these points, the reflections seemed to fuse into an archway of light and one could step through into another pa.s.sage. Alystra lost all conscious track of their twistings and turnings, and at last they emerged into a long, perfectly straight tunnel through which blew a cold and stead nd. It stretched horizontally for hundreds of feet in either , direction, and its far ends were tiny circles of light."i don't like this place," alystra complained. "It's cold."

She had probably never before experienced real coldness in her life, and alvin felt somewhat guilty. He should have warned her to bring a cloak-and a good one, for all clothes in diaspar were purely ornamental and quite useless as a protection. Since her discomfort was entirely his fault, he handed over his cloak without a word. There was no trace of gallantry in this; the equality of the s.e.xes had been complete for far too long for such conventions to survive. Had matters been the other way around, alystra would have given alvin her cloak and he would have as automatically accepted. It was not unpleasant walking with the wind behind them, and they soon reached the end of the tunnel. A wide-meshed filigree of stone prevented them from going farther, which was just as well, for they stood on the brink of nothingness. The great air duct opened on the sheer face of the tower, and below them was a vertical drop of at least a thousand feet. They were high upon the outer ramparts of the city, and diaspar lay spread beneath them as few in their world could ever have seen it. The view was the obverse of the one that alvin had obtained from the center of the park. He could look down upon the concentric waves of stone and metal as they descended in mile-long sweeps toward the heart of the city. Far away, partly hidden by the intervening towers, he could glimpse the distant fields and trees and the eternally circling river. Further still, the remoter bastions of diaspar climbed once more toward the sky. Beside him, alystra was sharing the view with pleasure but with no surprise. She had seen the city countless times before from other, almost equally well-placed vantage points-and in considerably more comfort. "That's our world-all of it," said alvin. "Now i want to show you something else." he turned away from the grat-ing and began to walk toward the distant circle of light at the far end of the tunnel. The wind was cold against his lightly clad body, but he scarcely noticed the discomfort as he walked forward into the air stream. He had gone only a little way when he realized that alystra was making no attempt to follow. She stood watching, her borrowed cloak streaming down the wind, one hand half raised to her face. Alvin saw her lips move, but the words did not reach him. He looked back at her first with astonish-ment then with an impatience that was not totally devoid of pity. What jeserac had said was true. She could not fol-low him. She had realized the meaning of that remote circle of light from which the wind blew forever into diaspar. Behind alystra was the known world, full of wonder yet empty of surprise, drifting like a brilliant but tightly closed bubble down the river of time. Ahead, separated from her by no more than the span of a few footsteps, was the empty wilderness-the world of the desert-the world of the invaders.

Alvin walked back to join her and was surprised to find that she was trembling. "Why are you frightened?" he asked. "We're still safely here in diaspar. You've looked out of that window behind us surely you can look out of this one as well!" alystra was staring at him as if he was some strange mon-ster. By her standards, indeed, he was. "I couldn't do it," she said at last. "Even thinking about it makes me feel colder than this wind. Don't go any farther, alvin!" "but there's no logic in it!" alvin persisted remorselessly. "What possible harm would it do you to walk to the end of this corridor and look out? It's strange and lonely out there but it isn't horrible. In fact, the longer i look the more beautiful i think-" alystra did not stay to hear him finish. She turned on her heels and fled back down the long ramp that had brought them up through the floor of this tunnel. Alvin made no attempt to stop her, since that would have involved the bad manners of imposing one's will upon another. Persuasion, he could see would have been utterly useless. He knew that alystra would not pause until she had returned to her com-panions. There was no danger that she would lose herself m the labyrinths of the city, for she would have no dif-ficulty in retracing her footsteps. An instinctive ability to extricate himself from even the most complex of mazes had been merely one of the many accomplishments man had learned since he started to live in cities. The long-extinct rat had been forced to acquire similar skills when he left the fields and threw in his lot with humanity. Alvin waited for a moment, as if half-expecting alystra to return. He was not surprised at her reaction only at its violence and irrationality. Though he was sincerely sorry that she had gone, he could not help wishing that she had re membered to leave the cloak. It was not only cold, but it was also hard work moving against the wind which sighed through the lungs of the city. Alvin was fighting both the air current and whatever force it was that kept it moving. Not until he had reached the stone grille and could lock his arms around its bars, could he afford to relax. There was just sufficient room for him to force his head through the opening, and even so his view was slightly restricted, as the entrance to the duct was partly recessed into the city's wall. Yet he could see enough. Thousands of feet below, the sunlight was taking leave of the desert. The almost horizontal rays struck through the grating and threw a weird pattern of gold and shadow far down the tunnel. Alvin shaded his eyes against the glare and peered down at the land upon which no man had walked for unknown ages. He might have been looking at an eternally frozen sea. For mile after mile, the sand dunes undulated into the west, their contours grossly exaggerated by the slanting light. Here and there some caprice of the wind had carved curious whirlpools and gullies in the sand, so that it was sometimes hard to realize that none of this sculpture was the work of intelligence. At a very great distance, so far away indeed that he had no way of judging their remoteness, was a range of softly rounded hills. They had been a disappointment to alvin; he would have given much to have seen in reality the soaring mountains of the ancient records and of his own dreams. The sun lay upon the rim of the hills, its light tamed and reddened by the hundreds of miles of atmosphere it was traversing. There were two great black spots upon its disc; alvin had learned from his studies that such things existed, but he was surprised that he could see them so easily. They seemed almost like a pair of eyes peering back at him as he crouched in his lonely spy hole with the wind whistling ceaselessly past his ears. There was no twilight. With the going of the sun, the pools of shadow lying among the sand dunes flowed swiftly together in one vast lake of darkness. Color ebbed from the sky; the warm reds and golds drained away leaving an antarctic blue that deepened and deepened into night. Alvin waited for that breathless moment that he alone of all man-kind had known-the moment when the first star shivers into life. It had been many weeks since he had last come to this place, and he knew that the pattern of the night sky must have changed meanwhile. Even so, he was not prepared for his first glimpse of the seven suns. They could have no other name; the phrase leaped un-bidden to his lips. They formed a tiny, very compact and astonishingly symmetrical group against the afterglow of sun-set. Six of them were arranged in a slightly flattened ellipse, which, alvin was sure, was in reality a perfect circle, slightly tilted toward the line of vision. Each star was a different color; he could pick out red, blue, gold, and green, but the other tints eluded his eye. At the precise center of the forma-tion was a single white giant-the brightest star in all the visible sky. The whole group looked exactly like a piece of jewelry; it seemed incredible, and beyond all stretching of the laws of chance, that naure could ever have contrived so perfect a pattern. As his eyes grew slowly accustomed to the darkness, alvin could make out the great misty veil that had once been called the milky way. It stretched from the zenith down to the horizon, and the seven suns were entangled in its folds. The other stars had now emerged to challenge them, and their random groupings only emphasized the enigma of that perfect symmetry. It was almost as if some power had de-liberately opposed the disorder of the natural universe by setting its sign upon the stars. Ten times, no more, the galaxy had turned upon its axis since man first walked on earth. By its own standards, that was but a moment. Yet in that short period it had changed completely-changed far more than it had any right to do in the natural course of events. The great suns that had once burned so fiercely in the pride of youth were now guttering to their doom. But alvin had never seen the heavens in their ancient glory, and so was unaware of all that had been lost. The cold, seeping through into his bones, drove him back to the city. He extricated himself from the grating and rubbed the circulation back into his limbs. Ahead of him, down the tunnel, the light streaming out from diaspar was so brilliant that for a moment he had to avert his eyes. Outside the city there were such things as day and night, but within it there was only eternal day. As the sun descended the sky above diaspar would fill with light and no one would notice when the natural illuminati