The world had gone very far since, hour upon hour, the first cavemen had patiently chipped their arrowheads and knives from the stubborn stone.

             "Our problem now," said Rorden, "is to get into touch with the creature. It can never have any direct knowledge of Man, for there's no way in which we can affect its consciousness. If my information's correct, there must be an interpreting machine somewhere. That was a type of robot that could convert human instructions into commands that the Master Robots could understand. They were pure intelligence with little memory—just as this is a tremendous memory with relatively little intelligence."

             Alvin considered for a moment. Then he pointed to his own robot.

             "Why not use it?" he suggested. "Robots have very literal minds. It won't refuse to pass on our instructions, for I doubt if the Master ever thought of this situation."

             Rorden laughed.

             "I don't suppose he did, but since there's a machine specially built for the job I think it would be best to use it."

             The Interpreter was a very small affair, a horseshoe-shaped construction built around a vision screen which lit up as they approached. Of all the machines in this great cavern, it was the only one which had shown any cognizance of Man, and its greeting seemed a little contemptuous. For on the screen appeared the words:

             STATE YOUR PROBLEM PLEASE THINK CLEARLY

             Ignoring the implied insult, Alvin began his story. Though he had communicated with robots by speech or thought on countless occasions, he felt now that he was addressing something more than a machine. Lifeless though this creature was, it possessed an intelligence that might be greater than his own. It was a strange thought, but it did not depress him unduly—for of what use was intelligence alone?

             His words died away and the silence of that overpowering place crowded back upon them. For a moment the screen was filled with swirling mist, then the haze cleared and the machine replied:

             REPAIR IMPOSSIBLE ROBOT UNKNOWN TYPE

             Alvin turned to his friend with a gesture of disappointment, but even as he did so the lettering changed and a second message appeared:

             DUPLICATION COMPLETED PLEASE CHECK AND SIGN

             Simultaneously a red light began to flash above a horizontal panel Alvin had not noticed before, and was certain he must have seen had it been there earlier. Puzzled, he bent toward it, but a shout from Rorden made him look around in surprise. The other was pointing toward the great Master Robot, where Alvin had left his own machine a few minutes before.

             It had not moved, but it had multiplied. Hanging in the air beside it was a duplicate so exact that Alvin could not tell which was the original and which the copy.

             "I was watching when it happened," said Rorden excitedly. "It suddenly seemed to extend, as if millions of replicas had come into existence on either side of it. Then all the images except these two disappeared. The one on the right is the original."

             THE C O U N C I L

             Alvin was still stunned, but slowly he began to realize what must have happened. His robot could not be forced to disobey the orders given it so long ago, but a duplicate could be made with all its knowledge yet with the unbreakable memory-block removed. Beautiful though the solution was, the mind would be unwise to dwell too long upon the powers that made it possible.

             The robots moved as one when Alvin called them toward him. Speaking his commands, as he often did for Rorden's benefit, he asked again the question he had put so many times in different forms.

             "Can you tell me how your first master reached Shalmirane?"

             Rorden wished his mind could intercept the soundless replies, of which he had never been able to catch even a fragment. But this time there was little need, for the glad smile that spread across Alvin's face was sufficient answer.

             The boy looked at him triumphantly.

             "Number One is just the same," he said, "but Two is willing to talk."

             "I think we should wait until we're home again before we begin to ask questions," said Rorden, practical as ever. "We'll need the Associators and Recorders when we start."

             Impatient though he was, Alvin had to admit the wisdom of the advice. As he turned to go, Rorden smiled at his eagerness and said quietly:

             "Haven't you forgotten something?"

             The red light on the Interpreter was still flashing, and its message still glowed on the screen.

             PLEASE CHECK AND SIGN

             Alvin walked to the machine and examined the panel above which the light was blinking. Set in it was a window of some almost invisible substance, supporting a stylus which passed vertically through it. The point of the stylus rested on a sheet of white material which already bore several signatures and dates. The last of them was almost fifty thousand years ago, and Alvin recognized the name as that of a recent President of the Council. Above it only two other names were visible, neither of which meant anything to him or to Rorden. Nor was this very surprising, for they had been written twenty-three and fifty-seven million years before.

             Alvin could see no purpose for this ritual, but he knew that he could never fathom the workings of the minds that had built this place. With a slight feeling of unreality he grasped the stylus and began to write his name. The instrument seemed completely free to move in the horizontal plane, for in that direction the window offered no more resistance than the wall of a soap bubble. Yet his full strength was incapable of moving it vertically: he knew, because he tried.

             Carefully he wrote the date and released the stylus. It moved slowly back across the sheet to its original position—and the panel with its winking light was gone.

             As Alvin walked away, he wondered why his predecessors had come here and what they had sought from the machine. No doubt, thousands or millions of years in the future, other men would look into that panel and ask themselves: "Who was Alvin of Loronei?" Or would they? Perhaps they would exclaim instead: "Look! Here's Alvin's signature!"

             The thought was not untypical of him in his present mood, but he knew better than to share it with his friend.

             At the entrance to the corridor they looked back across the cave, and the illusion was stronger than ever. Lying beneath them was a dead city of strange white buildings, a city bleached by the fierce light not meant for human eyes. Dead it might be, for it had never lived, but Alvin knew that when Diaspar had passed away these machines would still be here, never turning their minds from the thoughts greater men than he had given them long ago.

             They spoke little on the way back through the streets of Diaspar, streets bathed with sunlight which seemed pale and wan after the glare of the machine city. Each in his own way was thinking of the knowledge that would soon be his, and neither had any regard for the beauty of the great towers drifting past, or the curious glances of their fellow citizens.

             It was strange, thought Alvin, how everything that had happened to him led up to this moment. He knew well enough that men were makers of their own destinies, yet since he had met Rorden events seemed to have moved automatically toward a predetermined goal. Alaine's message—Lys—Shalmirane—at every stage he might have turned aside with unseeing eyes, but something had led him on. It was pleasant to pretend that Fate had favored him, but his rational mind knew better. Any man might have found the path his footsteps had traced, and countless times in the past ages others must have gone almost as far. He was simply the first to be lucky.