The dense center was dangerous. Supernovas drove shock waves through fragile solar systems.

Protons sleeted down on worlds, sterilizing them. Stars swooped near each other, scrambling up planetary orbits and raining down comets upon them. The inner zone was a dead zone.

But a bit further out, the interstellar weather was better. Planets capable of sustaining organic life began their slow winding path upward toward life and intelligence within the first billion or two years after the galaxy formed. An Earth-like world that took 4.5 billion years to produce smart creatures would have done so about four billion years ago.

In that much time, intelligence might have died out, arisen again, and gotten inconceivably rich. The beyond-all-reckoning wealthy beings near the center could afford to lavish a pittance on a luxury-blaring their presence out to all those crouched out in the galactic suburbs, just getting started in the interstellar game.

Whatever forms dwelled further in toward the center, they knew the basic symmetry of the spiral.

This suggested that the natural corridor for communication is along the spiral's radius, a simple direction known to everyone. This maximized the number of stars within a telescope's view. A radius is better than aiming along a spiral arm, since the arm curves away from any straight-line view. So a beacon should broadcast outward in both directions from near the center.

So, rather than look nearby, the ancient Search for Extraterrestrial Intelligence searchers began to look inward. They pointed their antennas in a narrow angle toward the constellation Sagittarius. They listened for the big spenders to shout at the less prosperous, the younger, the unsophisticated.

But how often to cup an ear? If Earth was mediocre, near the middle in planetary properties, then its day and year were roughly typical. These were the natural ranges any world would follow: a daily cycle atop an annual sway of climate.

If aliens were anything like us, they might then broadcast for a day, once a year. But which day?

There was no way to tell-so the Search for Extraterrestrial Intelligence searchers began to listen every day, for roughly a half hour, usually as the radio astronomers got all their instruments calibrated. They watched for narrow-band signals that stood out even against the bright hub's glow.

Radio astronomers had to know what frequency to listen to, as well. The universe is full of electromagnetic noise at all wavelengths from the size of atoms to those of planets. Quite a din.

There was an old argument that water-based life might pick the "watering hole"-a band near 1 billion cycles/second where both water and hydroxyl molecules radiate strongly. Maybe not right on top of those signals, but nearby, because that's also in the minimum of all the galaxy's background noise.

Conventional Search for Extraterrestrial Intelligence had spent a lot of effort looking for nearby sources, shifting to their rest frame, and then eavesdropping on certain frequencies in that frame. But a beacon strategy could plausibly presume that the rest frame of the galactic center was the obviousgathering spot, so anyone broadcasting would choose a frequency near the "watering hole" frequency of the galaxy's exact center.

Piggy-backing on existing observing agendas, astronomers could listen to a billion stars at once.

Within two years, the strategy worked. One of the first beacons found was from the Sagittarius Architecture.

Most of the signals proved to have a common deep motivation. Their ancient societies, feeling their energies ebb, yet treasuring their trove of accumulated art, wisdom and insight, wanted to pass this on.

Not just by leaving it in a vast museum somewhere, hoping some younger species might come calling someday. Instead, many built a robotic funeral pyre fed by their star's energies, blaring out tides of timeless greatness: My name is Ozymandias, King of Kings, Look on my works, ye Mighty, and despair!

as the poet Percy Bysshe Shelley had put it, witnessing the ruins of ancient Egypt, in Afrik.

At the very beginnings of the library, humanity found that it was coming in on an extended discourse, an ancient inter-stellar conversation, without notes or history readily provided. Only slowly did the cyber-cryptographers fathom that most alien cultures were truly vast, far larger than the sum of all human societies. And much older.

Before actual contact, nobody had really thought the problem through. Historically, Englishmen had plenty of trouble understanding the shadings of, say, the Ozzie Bushmen. Multiply that by thousands of other Earthly and solar system cultures and then square the difficulty, to allow for the problem of expressing it all in sentences-or at least, linear symbolic sequences. Square the complexity again to allow for the abyss separating humanity from any alien culture.

The answer was obvious: any alien translator program had to be as smart as a human. And usually much more so.

The first transmission from any civilization contained elementary signs, to build a vocabulary. That much even human scientists had guessed. But then came incomprehensible slabs, digital Rosetta stones telling how to build a simulated alien mind that could talk down to mere first-timers.

The better part of a century went by before humans worked out how to copy and then represent alien minds in silicon. Finally the Alien Library was built, to care for the Minds and Messages it encased.

To extract from them knowledge, art, history, and kinds of knowing for which humans might very well have no name.

And to negotiate with them. The cyber-aliens had their own motivations.

"I don't understand your last statement."

I do not need to be told that. You signal body-defiance with your crossed arms, barrier gestures, pursed lips, contradictory eyebrow slants.

"But these tensor topologies are not relevant to what we were discussing."

They are your reward.

"For what?"

Giving me of your essence. By wearing ordinary clothes, as I asked, and thus displaying your overt signals.

"I thought we were discussing the Heliosphere problem."

We were. But you primates can never say only one thing at a time to such as We.

She felt acutely uncomfortable. "Uh, this picture you gave me...I can see this is some sort of cylindrical tunnel through-"

The plasma torus of your gas giant world, Jupiter. I suggest it as a way to funnel currents from the moon, lo.

"I appreciate this, and will forward it-"

There is more to know, before your level of technology-forgive me, but it is still crude, and will be so for far longer than you surmise-can make full use of this defense. Ruth suppressed her impulse to widen her eyes. Defense? Was this it? A sudden solution? "I'm not a physiker-"

Nor need you be. I intercept your host of messages, all unspoken. Your pelvis is visible beneath your shift, wider and rotated back slightly more than the male Supplicants who come to Us. Waist more slender, thighs thicker. Navel deeper, belly longer. Specializations impossible to suppress.

Where was it-They-going with this? "Those are just me, not messages."

It is becoming of you to deny them. Like your hourglass shape perceived even at a distance, say, across an ancient plain at great distance. Your thighs admit an obligingly wider space, an inward slope to the thickened thighs, that gives an almost knock-kneed appearance.

"I beg your pardon-"

A pleasant saying, that-meaning that We have overstepped (another gesture) your boundaries? But I merely seek knowledge for my own repository.

"I-we-don't like being taken apart like this!"

But reduction to essentials is your primary mental habit.

"Not reducing people!"

Ah, but having done this to the outside world, you surely cannot object to having the same method applied to yourselves.

"People don't like being dissected."

Your science made such great strides-unusual upon the grander stage of worlds-precisely because you could dexterously divide your attentions into small units, all the better to understand the whole.

When They got like this it was best to humor Them. "People don't like it. That is a social mannerism, maybe, but one we feel about."

And I seek more.

The sudden grave way the Sagittarius said this chilled her.

Siloh was not happy, though it took a lot of time to figure this out. The trouble with Noughts was their damned lack of signals. No slight downward tug of lips to signal provisional disapproval, no sideways glance to open a possibility. Just the facts, Ma'am. "So it is giving you tantalizing bits."

"They, not It. Sometimes I feel I'm talking to several different minds at once."

"It has said the same about us."

The conventional theory of human minds was that they were a kind of legislature, always making deals between differing interests. Only by attaining a plurality could anyone make a decision. She bit her lip to not give away anything, then realized that her bite was visible, too. "We're a whole species.

They're a simulation of one."

Siloh made a gesture she could not read. She had expected some congratulations on her work, but then, Siloh was a Nought, and had little use for most human social lubrications. He said slowly, "This cylinder through the Io plasma-the physikers say it is intriguing."

"How? I thought the intruding interstellar plasma was overpowering everything."

"It is. We lost Ganymede Nation today."

She gasped. "I hadn't heard."

"You have been immersed in your studies, as is fitting."

"Does Catkejen know?"

"She has been told."

Not by you, I hope . Siloh was not exactly the sympathetic type. "I should go to her."

"Wait until our business is finished."

"But I-"

"Wait."

Siloh leaned across its broad work plain, which responded by offering information. Ruth crooked her neck but could not make out what hung shimmering in the air before Siloh. Of course; this was a well designed office, so that she could not read its many ingrained inputs. He was probably summoninginformation all the while he talked to her, without her knowing it. Whatever he had learned, he sat back with a contented, small smile. "I believe the Sagittarius Congruence is emerging in full, to tantalize you."

"Congruence?"

"A deeper layer to its intelligence. You should not be deceived into thinking of it as remotely like us.

We are comparatively simple creatures." Siloh sat back, steepling its fingers and peering into them, a studied pose. "Never does the Sagittarius think of only a few moves into its game."

"So you agree with Youstani, a Translator Supreme from the twenty-fifth century, that the essential nature of Sagittarius is to see all conversations as a game?"

"Are ours different?" A sudden smile creased his leathery face, a split utterly without mirth.

"I would hope so."

"Then you shall often be deceived."

She went to their apartment immediately, but someone had gotten there before her. It was dark, but she caught muffled sounds from the living room. Was Catkejen crying?

Earth's crescent shed a dim glow into the room. She stepped into the portal of the living room and in the gloom saw someone on the viewing pallet. A low whimper drifted in the darkness, repeating, soft and sad, like crying, yes- But there were two people there. And the sobbing carried both grief and passion, agony and ecstasy.

An ancient tide ran in the room's shadowed musk.

The other person was Geoffrey. Moving with a slow rhythm, he was administering a kind of sympathy Ruth certainly could not. And she had not had the slightest clue of this relationship between them. A pang forked through her. The pain surprised her. She made her way out quietly.

Catkejen's family had not made it out from Ganymede. She had to go through the rituals and words that soften the hard edges of life. She went for a long hike in the domes, by herself. When she returned she was quieter, worked long hours and took up sewing.

The somber prospects of the Ganymede loss cast a pall over all humanity, and affected the Library's work. This disaster was unparalleled in human history, greater even than the Nation Wars.

Still, solid work helped for a while. But after weeks, Ruth needed a break, and there weren't many at the Library. Anything physical beckoned. She had gone for a swim in the spherical pool, of course, enjoying the challenge. And flown in broad swoops across the Greater Dome on plumes of hot air. But a simmering frustration remained. Life had changed.

With Catkejen she had developed a new, friendly, work-buddy relationship with Geoffrey. Much of this was done without words, a negotiation of nuances. They never spoke of that moment in the apartment, and Ruth did not know if they had sensed her presence.

Perhaps more than ever, Geoffrey amused them with his quick talk and artful stunts. Ruth admired his physicality, the yeasty smell of him as he laughed and cavorted. HiGeers were known for their focus, which athletics repaid in careers of remarkable performance. The typical HiGee career began in sports and moved later to work in arduous climes, sites in the solar system where human strength and endurance still counted, because machines were not dexterous and supple enough.

Some said the HiGeer concentration might have come from a side effect of their high-spin, centrifugal doughnut habitats. Somehow Geoffrey's concentration came out as a life-of-the-party energy, even after his long hours in intense rapport with his own research.

Appropriately, he was working on the Andromeda Manifold, a knotty tangle of intelligences that stressed the embodied nature of their parent species. Geoffrey's superb nervous system, and especially his exact hand-eye coordination, gave him unusual access to the Manifold. While he joked about this, most of what he found could not be conveyed in words at all. That was one of the lessons of the Library-that other intelligences sensed the world, and the body's relation to it, quite differently. The ghost of Cartesian duality still haunted human thinking.

Together the three of them hiked the larger craters. All good for the body, but Ruth's spirit was troubled. Her own work was not going well. She could scarcely follow some of the Architecture's conversations. Still less comprehensible were the eerie sensoria it projected to her-sometimes, the only way it would take part in their discourse, for weeks on end.

Finally, frustrated, she broke off connection and did not return for a month. She devoted herself instead to historical records of earlier Sagittarius discourse. From those had come some useful technical inventions, a classic linear text, even a new digital art form. But that had been centuries ago.

Reluctantly she went back into her pod and returned to linear speech mode. "I don't know what you intend by these tonal conduits," she said to the Sagittarius-after all. It probably had an original point of view, even upon its own motivations.

I was dispatched into the Realm to both carry my Creators' essentials, to propagate their supreme Cause, and to gather knowing-wisdom for them.

So it spoke of itself as "I" today-meaning that she was dealing with a shrunken fraction of the Architecture. Was it losing interest? Or withholding itself, after she had stayed away?

I have other functions, as well. Any immortal intelligence must police its own mentation.

Now what did that mean? Suddenly, all over her body washed sheets of some strange signal she could not grasp. The scatter-shot impulses aroused a pulse-quickening unease in her. Concentrate.

"But...but your home world is toward the galactic center, at least twenty thousand light years away. So much time has passed-"

Quite so-my Creators may be long extinct. Probabilities suggest so. I gather from your information, and mine, that the mean lifetime for civilizations in the Realm is comparable to their/our span.

"So there may be no reason for you to gather information from us at all. You can't send it to them any more." She could not keep the tensions from her voice. In earlier weeks of incessant pod time, she had relied upon her pod's programming to disguise her transmission. And of course, It knew this. Was anything lost on it?

Our motivations do not change. We are eternally a dutiful servant, as are you.