Direct atomic power. Direct utilization of the force of the flying neutrons. No more ridiculous business of using a reactor to drive a steam engine, or boil off something for a jet exhaust--processes that were as primitive and wasteful as burning gunpowder to keep yourself warm. Chemical jets would carry his spaceship above the atmosphere. Then would come the thrilling order, "Set sail for Mars!" The vast umbrella would unfold and open out around the stern, its rear or Earthward side a gleaming expanse of radioactive ribbon perhaps only an atom thick and backed with a material that would reflect neutrons. Atoms in the ribbon would split, blasting neutrons astern at fantastic velocities. Reaction would send the spaceship hurtling forward. In airless space, the expanse of sails would naturally not retard the ship. More radioactive ribbon, manufactured as needed in the ship itself, would feed out onto the sail as that already there became exhausted. A spaceship with direct nuclear drive--and he, a Thinker, had conceived it completely except for the technical details! Having strengthened his mind by hard years of somno-learning, mind-casting, memory-straightening, and sensory training, he had assured himself of the executive power to control the technicians and direct their specialized abilities. Together they would build the true Mars rocket. But that would only be a beginning. They would build the true Mind Bomb. They would build the true Selective Microbe Slayer. They would discover the true laws of ESP and the inner life. They would even--his imagination hesitated a moment, then strode boldly forward--build the true Maizie! And then ... then the Thinkers would be on even terms with the scientists. Rather, they'd be far ahead. No more deception. He was so exalted by this thought that he almost let the slideway carry him past his door. He stepped inside and called, "Caddy!" He waited a moment, then walked through the apartment, but she wasn't there. * * * * * Confound the girl, he couldn't help thinking. This morning, when she should have made herself scarce, she'd sprawled about sleeping. Now, when he felt like seeing her, when her presence would have added a pleasant final touch to his glowing mood, she chose to be absent. He really should use his hypnotic control on her, he decided, and again there sprang into his mind the word--a pet form of her name--that would send her into obedient trance. No, he told himself again, that was to be reserved for some moment of crisis or desperate danger, when he would need someone to strike suddenly and unquestioningly for himself and mankind. Caddy was merely a wilful and rather silly girl, incapable at present of understanding the tremendous tensions under which he operated. When he had time for it, he would train her up to be a fitting companion without hypnosis.