"The other survival factor was to fight. The fighters died an earlier death than did those that ran, and they had fewer progeny. But those fighters that lived ruled the tribes. "During each generation these separate instincts developed and became more virile. The numbers of the fleers propagated and soon the mass of the human race consisted of their descendants. The fighters, however, ruled the tribes, as was logical. They were the doers, and became the leaders. "I, Mr. Ostby, am a direct descendant of this long line of fighters--perhaps its culmination. I have never known fear, and I never flee! I have inherited the strength of those ancestors, and I rule now because I am the strongest man in the world, both mentally and physically. The world belongs to the strong, and I am the strongest. Let that weigh heavily in every thought you have concerning me." Ostby found himself wondering in amazement at the colossal pride that could give birth to such thought processes. "Now," the Imperator went on, "let me give you one last warning before you leave. You may be in line for my position, and you must prove to me that you are strong enough to take my place, if that ever becomes necessary. On the other hand if your strength evidences itself by the slightest opposition to me, I will kill you. Thus you have a fine line to walk, with your life hanging in the balance. "This concludes our interview until later this afternoon," the Imperator said. "I would suggest, in the meantime, that you consult the Brain. He can supply you with an understanding of our background which you may find useful." * * * * * Ostby was glad the Imperator had suggested his speaking with the Brain. He had made his decision now, but there was much the Brain could tell him that he needed to know. He walked down one flight and into the room housing the Brain. When he arrived he found it awake and obviously watching him. Once again he experienced a vast discomfort in meeting that giant eye, with its mottled apperception. He wondered uneasily if it had the power to read his mind. Ostby's unease was not lessened by the Brain's first words. "You have finished your interview with the Imperator," it said. "Evidently you were wise enough not to antagonize him or you would not be here now. Is there anything special you would like to ask me?" There was much he wanted to learn from the Brain and Ostby had no hesitation in replying. "What are you?" he asked without preliminaries. "How old are you, and just what is the extent of your powers?" For a moment Ostby was afraid that he had, in some way, made a wrong approach, and that the Brain would refuse to answer him, for it was silent. But finally it said, quietly, "Perhaps one question at a time would be better for both of us. I can answer directly then, and you will be able to assimilate the answers more easily. Some of them will have many ramifications and require supplementary explanations.