He started at the left and began working his way around.

He’d chosen the section on space travel more or less at random; it had looked less crowded than the others. The romance of space was not in Phssthpok’s soul. He kept with it rather than start over elsewhere. He might need every minute of his thirty-four years of grace no matter where be chose to work. In twenty-eight years he read every book in the Astronautics section, and still he had found nothing that drastically needed doing.

Start a migration project? It simply wasn’t that urgent. The Pak sun had at least hundreds of millions of years to live… longer than the Pak species, probably, given the constant state of war. And the chance of disaster would be high. Yellow suns were scarce in the galactic core; they would have to travel far… with the protector crew constantly fighting for control of the ship. Come to that, the cores of galaxies could sometimes explode in a chain reaction of supernovae. A migration project really should travel into the arms.

The first expedition to try that had met a horrible fate.

So. Join the Library staff? He’d thought of it many times, but the answer always came out the same. No matter what phase of the Library he concerned himself with, his life would depend on others. To retain his will to live he would need to know that all Pak would benefit from his aspect of Library work. Let there be a dry spell in new discoveries, let his faith flag, and he would find himself no longer hungry.

It was frightening not to be hungry. During the last few decades it had happened several times. Each time he would force himself to reread the communications from the Valley of Pitchok. The latest communication always told him that Ttuss had been alive when it was sent. Gradually his appetite would come back. Without Ttuss he would be dead.

He had investigated the librarians. Their lives were usually short. Joining the staff was no answer.

Find a way to keep Ttuss alive? If he could do that he would have used the method on himself.

Study theoretical astronomy? He had some ideas, but they would not help the Pak species. The Pak did not seek abstract knowledge. Mine the asteroids? The asteroids of this and nearby stars were as thoroughly mined out as the surface of the planet had often been, with the difference that convection currents in the planet’s interior eventually replaced worked-out mines. He should have gone in for metal reclamation. Now it was too late to change studies. Put plastic-bubble cities in orbit to provide more living room for breeders? Nonsense: too vulnerable to capture or accidental destruction.

One day Phssthpok’s appetite was gone. The letters from the Valley of Pitchok did not help; he didn’t believe them. He thought of returning to the valley, but he knew he would starve to death on the way. When he was sure, he sat down against a wall, the last in a line of protectors who also did not eat, who were waiting to die.

A week passed. The librarians found that two at the head of the line were dead. They picked them up, a pair of skeletons clothed in dry, wrinkled leather armor, and carried them away.

Phssthpok remembered a book.

He still had the strength to reach it.

He read carefully, with the book in one hand and a root in the other. Presently he ate the root…

The ship had been a roughly cylindrical asteroid, reasonably pure nickel-iron with stony strata running through it, about six miles long and four through. A group of childless protectors had carved it out with solar mirrors and built into it a small life-support and controls system, a larger frozen-sleep chamber, a breeder atomic pile and generator, a dirigible ion drive, and an enormous cesium tank. They had found it necessary to exterminate the protectors of a large family in order to get control of a thousand breeders. With two protectors as pilots and seventy more in frozen sleep with the thousand breeders, with a careful selection of the beneficial lifeforms of the Pak world, they set out into one arm of the galaxy.

Though their knowledge was three million years scantier than Phssthpok’s, they had good reason for choosing the galaxy’s outer reaches. They’d have a better chance of finding yellow suns out there, and a better chance to find a double planet at the right distance. Perturbations from stars an average of half a light year apart made double planets scarce in the galactic core; and there was reason to think that only an oversized moon could give any world an atmosphere capable of supporting Paklike life.

An ion drive and a certain amount of cesium… They expected to move slowly, and they did. At twelve thousand miles per second relative to the Pak sun, they coasted. They fired a laser message back at the Pak sun to tell the Library that the ion drive had worked. The blueprints were somewhere in the Library, with a list of suggested design changes.

Phssthpok was not interested. He moved on to the last section, which was nearly half a million years more recent.

It was a record of a laser message that had come plowing through the Pak system, torn and attenuated and garbled by dust clouds and distance, in a language no longer spoken. The librarians had translated it and filed it here. It must have been retranslated hundreds of times since then. Hundreds of searchers like Phssthpok must have read it, and wondered about the part of the story they could never know, and passed on…

But Phssthpok read it very carefully.

They had traveled deep into the galactic arms. Half the protectors had been gone at journey’s end, dying not of starvation or violence but of age. This was so unusual that a detailed medical description had been included as part of the message. They had passed yellow suns with no planets, others whose worlds were all gas giants. Yellow suns had gone by carrying worlds that might have been habitable; but all were too far off course to be reached on the maneuvering reserve of cesium. Galactic dust and the galaxy’s gravity had slowed their strange craft, increasing their maneuver reserve. The sky had darkened around them as suns became rare.

They had found a planet.

They had braked the ship. They had transferred what was left of the plutonium to the motors of landing craft, and gone down. The decision was not final; but if the planet failed to measure up they would have to work for decades to make their rockship spaceworthy again.

It had life. Some was inimical, but none that could not be handled. There was soil. The remaining protectors woke the breeders and turned them loose in the forests to be fruitful and multiply. They planted crops, dug mines, made machines to dig more mines, made machines to tend crops…

The black, nearly starless night sky bothered some, but they got used to it. The frequent rains bothered others, but did not hurt the breeders, so that was all right. There was room for all; the protectors did not even fight. None stopped eating. There were predators and bacteria to exterminate, there was a civilization to build, there was much to do.

With spring and summer came crops — and disaster. There was something wrong with the tree-of-life.

The colonists themselves did not understand what had gone wrong with the crop. Something had come up. It looked and tasted like tree-of-life, though the smell was wrong, somehow. But for all its effect on breeders and protectors alike, they might as well have been eating weeds.

They could not return to space. Their scant remaining store of roots represented an inflexible number of protector work-hours. They might refuel their cesium tanks, they might even build a plutonium-producing technology in the time they had left, but to find and reach another Pak-like world — no. And if they reached it, what guarantee had they that it would grow tree-of-life?

They had spent their last years building a laser beam powerful enough to pierce the dust clouds that hid them from the galactic core. They did not know that they had succeeded. They did not know what was wrong with the crop; they suspected the sparsity of a particular wavelength of starlight, or of starlight in general, though their experiments along those lines had produced nothing. They gave detailed information on the blood lines of their breeder passengers, in the hope that some of the lines might survive. And they asked for help.