He had stolen this-whatever it was. He had destroyed the derelict to cover his tracks. To break into the Pak archives was not only the logical next step, this time it was his idea.

He hesitated at a memory: of a face frozen in agony, of a visor filmed with blood.

Gritting his teeth, Louis extracted a random circuit module.

Naked-eye inspection revealed nothing. Scans yielded structural details but not meaning. Replacing the module, he inspected a second component with the same lack of enlightenment. He sampled a random scattering of modules across the equipment rack, and then systematically examined the three top tiers. Every scan and measurement went into his pocket comp.

The most common components were densely packed, three-dimensional matrices. Almost certainly memory arrays. And it was read-only memory, the bits permanently encoded as atomic substitutions in otherwise pure, defect-free, crystalline-silicon lattices.

Ausfaller's prisoner had spoken of Library knowledge scribed on metal pages. Pak could bomb themselves back to a stone age-and supposedly regularly did-and the Library would survive. Of course that was before the Pak fled the core explosion. The equipment Louis had recovered seemed to offer similar permanence with greatly improved portability.

It was a start. Louis latched the workroom door behind him and called it a day.

What about the circuits that weren't memory arrays? Access circuits, Louis guessed. Or mechanisms for decompressing compacted data. Or error-correction apparatus, for not even Pak engineering could prevent cosmic rays from inducing random errors. Or security mechanisms. Or- Why speculate? Louis went to his cabin and uploaded his findings to Voice. Voice, too, failed to deduce anything useful. Louis returned to the workroom.

Three fat stubs of insulated copper cable, their ends burnished like mirrors, protruded from the bottom of the rack. The remainder of the cables had been lopped off during the stepping-disc transfer between the Pak ship and Aegis. Aegis. To Louis the wiring looked like a power hookup. Wearing an insulated glove, he unplugged the cable stubs. The copper terminals beneath looked suitable for connecting power. To Louis the wiring looked like a power hookup. Wearing an insulated glove, he unplugged the cable stubs. The copper terminals beneath looked suitable for connecting power.

"Time for the smoke test," he muttered, straightening his improvised cables. He had had to synth alligator clips for quick disconnects. Nothing in Aegis Aegis' parts bins had sharp teeth.

He ran cables from the rack to one of his power supplies.

According to Nessus, Citizens had an adage: nothing ventured, nothing lost. Louis thought of that as he made the final connection.

No smoke.

Better yet, no pain. Louis released the breath he had not known he was holding.

LEDs now glowed in the rack. On his power supply, a virtual needle jittered about a simulated dial before settling at a modest output level. His RF receiver showed a new low-energy carrier signal.

The Pak equipment was ready to talk.

Heads craning, Nessus circled the test setup in Louis's workroom. "I am impressed."

"Thanks, but there is much left to learn." Louis summarized his experimentation over the past several days.

Too often those techniques were trial and error. Nessus managed not to flinch. "You have not gotten us killed. That is commendable."

"Now watch." Louis tapped the touchpad on one of his bench instruments: a network analyzer interfaced to a human-model pocket computer.

Gibberish flooded what had been an empty display. Nessus recognized characters from Interworld, but most of the symbols were unfamiliar to him. Text reached the bottom and the image began scrolling.

Louis said, "When the rack powers up, it broadcasts a short sequence of pulses. Identifying itself? Asking for a command? Whatever it is, I took it as an instance of an input/output protocol. It took some ... effort, but now I can elicit responses. Parts of the format appear to function as an index or address. When I vary that part of the message, the rack replies with different information."

Nessus caught the hesitation. Maybe he had had flinched. Trial and error? Madness! flinched. Trial and error? Madness!

"That said," Louis continued, "there is less here than meets the eye. The raw data stream from the box is clearly binary, but after that? Your guess is as good as mine.

"All data transfers have lengths in multiples of ten bits. Supposing that the Pak encode characters in ten-bit blocks, I assigned symbols to the 1024 possible values. I used Interworld characters for the most common bit patterns until I ran out. After that, the marks are computer-assigned squiggles.

"Presumably we're seeing Library data. But what does it mean? I can't say."

The workroom hatch opened and Achilles came-stomped-in. His heads swung in opposite directions, glancing about the workroom. "You cannot read it." He spoke in Interworld, adding a sprinkle of undertunes surely meaningless to Louis.

But not to Nessus. Achilles had gibed: I I know all that happens here. know all that happens here.

The Library might hold secrets to mitigate the situation with the Gw'oth. If so, the sooner the knowledge could be obtained the better. And Achilles, after his rogue assault on the Pak, would surely step off this ship directly into prison. He might as well do something for for the Concordance first. the Concordance first.

"Perhaps," Nessus said, "Louis will allow you to assist him."

Achilles raised his left foreleg. "Perhaps I will, if you first remove this ridiculous, insulting anklet. You control the ship. Where am I going to go?"

Louis was a fair mechanic: he understood what things could do. But how they did it? For that he needed help, and Voice remained, most of the time, off limits. Nessus was less technical than Louis. That left Achilles.

Achilles was brilliant.

Louis had queried at random into the Pak archive, hoping to find message formats that did something. something. He was far from a theory what any of it-query or response-meant. He was far from a theory what any of it-query or response-meant.

Achilles pored over the responses, comparing inputs and outputs, and occasionally encountering long, identical data blocks in the responses. That was sufficient hint for him to derive the addressing scheme within the Library message format, and the representation of digits.

They had translated their first Pak binary codes.

Achilles used the newfound numeric characters to define fundamental dimensionless constants, physical parameters independent of units of measure. (A few, like the ratio of rest masses of fundamental particles, Louis understood. Most, like something Achilles called the gravitational coupling constant, Louis did not.) Achilles used those numeric values to locate what had to be discussions of specific topics in physics. Citizen knowledge of those physical constants hinted at the content of nearby Pak text. Mathematical relationships implied additional meanings. Citizen translation software, until then without a point of departure, began to contribute.

"I need more data," Achilles complained.

Louis retrieved a cargo floater and moved two more racks of Pak gear to the shielded workroom. By the time he had braced the new racks in place and supplied them with power, Achilles had already begun identifying physics terms. Even among the first scattered snippets of Pak science, things he read-and Louis usually could not-made Achilles trill.

Pak and Puppeteer science had evidently reached enough similar conclusions about the universe to constitute a Rosetta Stone of sorts. Most terms Achilles encountered many times over, for the Library saved the discoveries of all clans, across countless cycles of collapse and rediscovery.

Concepts Achilles expected to find in proximity sometimes were not. He pondered that incongruity for a while, softly chanting to himself. "Ah," he finally said. "Active links." He suggested condescendingly that Louis might be able to work out the command formats that would follow such hyperlinks.

While Louis experimented, Achilles isolated simple two-, three-, and four-dimensional data structures in the data streams. He declared them flat, holographic, and animation images. Often he was right. Labels within the images suggested a few more physics terms.

Achilles was still dealing with half-recognized, ill-defined phrases scattered across a sea of untranslated data when Louis had his Eureka! Eureka! moment. moment.

17.

The waiting was the hardest part.

Nessus cowered, burrowed deep within a nest of soft cushions, as, in the ambiguous safety of hyperspace, Aegis Aegis crisscrossed the Library fleet. Again. He had come to his cabin to sleep, but sleep, as it had for days, eluded him. With one head he gulped warm carrot juice from a drink bulb; with the other he tugged and twisted at a mane already stirred beyond further disarray. crisscrossed the Library fleet. Again. He had come to his cabin to sleep, but sleep, as it had for days, eluded him. With one head he gulped warm carrot juice from a drink bulb; with the other he tugged and twisted at a mane already stirred beyond further disarray.

Almost as hard as the waiting was Achilles' gloating. Amid the clamoring by his faction for new Experimentalist Party leadership, keeping Achilles far from Hearth became the lesser evil. To the Hindmost, anyway. As Achilles had surely calculated when he advocated this mad scheme.

And so, as Achilles had urged, Aegis Aegis had reversed course. They could have been back on Hearth by now. Instead they leapt about the fringes and into the interstices of the Library fleet, siphoning knowledge. had reversed course. They could have been back on Hearth by now. Instead they leapt about the fringes and into the interstices of the Library fleet, siphoning knowledge.

Achilles grew more arrogant and insufferable by the day.

The extent of Achilles' influence had taken Nessus by surprise. He promised himself things would be different when he reached Hearth with the proof of Achilles' latest crimes-even as he worried political maneuvering might save Achilles yet again.

Especially if, as looked likely, Achilles returned with the knowledge of the Pak. Success had a way of excusing wrongs.

"Five minutes," Louis announced over the intercom. He was on the bridge.

"On my way." Nessus reluctantly uncurled and stood.

At the clatter of hooves, Louis glanced up from his console. "You look tired."

The twitchy drug user on Wunderland was gone, become someone on whom Nessus increasingly relied. It was hard to remember he had recruited Louis in desperation. Not every surprise was for the worse.

"I can rest on Hearth," Nessus said. And you, Louis, look as haggard as I feel.

Louis smiled. "One minute to dropout." Lips moving silently as he counted down the final seconds along with the timer, he took the hyperdrive controls, "And ... now."

Nessus' heads swiveled frantically as an arc of instruments and displays returned to life. From readings of magnetic fields and the light of fusion exhausts: no ramscoops within two hours' flight. From the radio backdrop: no diminution of message traffic to suggest any change in behavior among nearby Pak.

"We're safe," Louis said reassuringly. He said much the same each time they emerged to normal space. "We're still stealthed, and even the closest Pak are too distant to see us optically."

"In theory."

"Lots of radio traffic." Louis leaned back in his couch. "Not a surprise. These Pak are librarians. Of course they keep studying and indexing their archives. Even if they weren't librarians, what else would they have to do?"

Hunt for alien intruders sniffing at their flanks, Nessus thought.

"They must be constantly accessing files and adding hyperlinks to enrich the archives," Louis went on. (Nessus had heard it all before. Beowulf Shaeffer was a talker. Like stepfather, like stepson, perhaps. More likely, amid the insanity of this mission, Louis really spoke to reassure himself.) "With archives spread across the fleet, following hyperlinks usually involves inter-ship traffic. Quite possibly none of them know at any given moment which ramscoop has the nearest copy of the file they want. They have to broadcast their requests. It's why Argo Argo intercepted so much radio traffic among the ramscoops." intercepted so much radio traffic among the ramscoops."

That realization had turned Aegis Aegis around. That and spotting the potential of the hyperlinks. Both Louis's insights. around. That and spotting the potential of the hyperlinks. Both Louis's insights.

"Ready to deploy the buoy," Achilles called over the intercom.

"Acknowledged," Nessus responded.

"There it goes."

The cargo-hold hatch opened; over an external camera Nessus watched the comm-relay buoy recede.

The buoy's tumbling retreat was somehow a metaphor for the convoluted path that had brought them here.

Triggering a hyperlink requested the transfer of related data. Clicks, Louis called the download requests, the origin of the term lost in human computing history. So read through the salvaged archives, eliciting and recording the wireless download requests. Broadcast the recordings to Library ships. Siphon up the radioed responses. Use the salvaged equipment to administer the Pak comm protocols and decrypt responses.

Scan newly retrieved data for new hyperlinks and repeat.

But in the time a radioed click click took to reach a Pak ship, that ship might spot them. As quickly as a radioed response could reach them, so might a Pak laser beam. They had Achilles' experience to prove Pak lasers could outwit or overpower General Products' solar-flare shields. took to reach a Pak ship, that ship might spot them. As quickly as a radioed response could reach them, so might a Pak laser beam. They had Achilles' experience to prove Pak lasers could outwit or overpower General Products' solar-flare shields.

So: buoys.

"Buoy online," Louis announced. "Radio comm tests ... all pass. Hyperwave comm tests ... all pass. Onboard computer tests ... all pass. Power output ... nominal."

"Hyperwave uploads completed from ... twelve buoys." Nessus stared at his comm panel, hoping he had miscounted and sure he had not. He hurriedly scanned the upload logs. "Buoy six reported a ramscoop on approach and self-destructed." That made three losses.

"Cargo-hold hatch secured," Achilles reported.

Louis leaned toward his flight controls. "Returning to hyperspace in three. Two. One."

The view ports became soothing pastoral scenes.

Nessus trilled in relief. Another foray among the Pak in which they had not been ambushed.

How long could their luck last?

Louis squirmed on the copilot's crash couch, yawning.

If he wasn't so tired, he supposed he would wonder if they were accomplishing anything. No one had the time or energy to sift the incoming data. Maybe, once they finished here, during the long trip to the Fleet of Worlds.

On Hearth, scientists were salivating for a look at the Pak Library. They, too, had to wait. The highest bit rates that hyperwave transmitters could push through at this distance, even while drawing the ship's full power, scarcely handled speech and short text messages.

Coffee and adrenaline notwithstanding, Louis could hardly keep his eyes open. He thought fleetingly of stim pills-and recoiled. He would not not travel down that road again. travel down that road again.

Instead, stifling another yawn, he reviewed the ship's path.

Aegis raced back and forth across the Pak fleet. Safety lay in speed, in disappearing before any of the Pak could spot them. raced back and forth across the Pak fleet. Safety lay in speed, in disappearing before any of the Pak could spot them.

Success also lay in speed. Every passing moment carried the telltale gamma-ray pulse from Argo Argo's nuclear attack deeper into the Library fleet. Just as surely, the surreptitious probing of the Library revealed itself to Pak intrusion detectors. Unusual patterns of queries, Louis guessed. Whatever the reason, suspicions spread at light speed among the Pak. More and more ramscoops ignored clicks from the buoys. More and more buoys self-destructed, magnetic fuses denying hyperwave transceivers to the ramscoops swooping to investigate.

Yawning again, Louis reached for another drink bulb of coffee. Had Aegis Aegis not turned back when it had, the opportunity to ransack the Library would have been lost. Achilles had been correct about that. not turned back when it had, the opportunity to ransack the Library would have been lost. Achilles had been correct about that.

So Louis and Nessus hyperdrive-hopped Aegis Aegis ahead of the warning broadcasts. In time, awareness of intruders would reach the last of the ramscoops. At that moment the expedition's ability to pull information from the Library ended. ahead of the warning broadcasts. In time, awareness of intruders would reach the last of the ramscoops. At that moment the expedition's ability to pull information from the Library ended.

Or earlier, if their luck ran out.

It could happen so many ways. A Pak warship changing course or speed while Aegis Aegis was in hyperspace. Departing hyperspace a few seconds too soon or too late. Something he lacked the imagination even to consider. ... was in hyperspace. Departing hyperspace a few seconds too soon or too late. Something he lacked the imagination even to consider. ...

Keep your mind on your work.

Nessus was a bedraggled, insomniac mess, struggling more each day to maintain manic-crazy bravery. Achilles, after living through one encounter with the Pak, seemed permanently crazy-brave. Unless, as Louis increasingly sensed, Achilles was simply crazy.

As stressful as Louis found jumping about the Pak fleet, he had his pride. He could not not suggest retreat before a Puppeteer did. suggest retreat before a Puppeteer did.

The moment approached to emerge from hyperspace into another cluster of Library ships. "Dropping out in five minutes," Louis announced over the intercom. "Ready another buoy."

He tried not to notice the tremor in his hands.