"We built the sphere, set forces in it that made it, to the best of our knowledge, all powerful. We armed it with incredible weapons. We built into it the apparatus to warp space--an adaptation of the drive we once used on our space ships. Then, on the brain substance housed in the heart of this sphere, we impressed the individual consciousness of each living person, and the knowledge that each person had in his own mind, which included all the knowledge that the human race has gained in more than two million years. We blended into one mind the minds of the two hundred humans who remained alive. Housed in a substance that was eternal, sheltered in a sphere that could not be destroyed, it became an almost perfect mind. We thought it was perfect. We discarded our bodies, as outworn tools. Physically, the human race died. Mentally, it would live forever. "One thing we had never done--flown to the stars. We had reached the planets and had almost forgotten them. But the stars in the sky we had not reached. It was the last great voyage of discovery. "We set out for the stars. And we reached them!" The twinkling points of light that Jan Lippershey had shown to be suns lost in the immensity of space! The voice died into silence, seemed to rest, then whispered again. "And near Antares a meteor swarm struck us. Inconceivable powers were housed within this sphere. We tried to escape but the swarm was moving almost as fast as light. We tried to blast the meteors into nothingness, and we succeeded in this. But we could not succeed forever. Eventually even the powers of this sphere were near exhaustion. Thousands of pea-size meteors struck us. The force of those collisions cracked the sphere itself. In time we limped back to earth, limped back to a place where we could lie up and lick our wounds. "We discovered that the wounds would not heal, that the damage was irreparable. Energy was leaking from the sphere, a little by a little. Somehow we had erred in its construction. "Somehow we had gone down the wrong road, had taken the wrong turning. "We could not anticipate that this would happen, we could not see what would happen tomorrow. But we knew that our race, and your race, was dying here, that you, back in the mists of time, were moving down a road with death as your destiny. "The drive that carries a race is not lightly ended. "But the human race ended in us, in our error. "It was our mistake. It was our task to correct it, if we could. "We tried. "We could not go back through time, but we could force our thoughts back to certain cyclic periods. We could reach only a few periods, most of them too early or too late to meet our needs. Eventually we found a time that was right and a mind that could understand. To that mind we gave instructions, to Lee Garth...." The voice paused, sought for energy, slowly gathered it, then went on.