The masks could only have been designed to cover the darkest deceit, to cover the most terrifying treachery. How many officers and enlisted men on the Station were wearing masks? How many? And why? Was _every_ officer on the Station wearing one? If the masks were thought necessary, if their employment had been made mandatory, there could be only one explanation. Every officer and every enlisted man was masquerading. The Station was officered and manned by--a word he'd never liked from a dictionary of obsolete American slang came unbidden into his mind--_Phonies!_ The thought staggered him. For a moment he rejected it as inconceivable, outside the bounds of reason. But it remained on the perimeter of his consciousness and would not be dislodged. It came back and set itself down where its dominance over his mind could not be contested. What else _could_ it mean? Masks have only one purpose: to enable the wearer to avoid being recognized. Quite obviously the phony officers could be wearing masks for only one reason: to conceal their real identities while they manned the Stations, carrying on the tasks of the men they had displaced. Carrying on the tasks of the rightful officers, but with a difference. And that difference would almost certainly be criminal activity on a wide and daring scale. The only question remaining to be answered was how high did that activity ascend? Did it ascend to the very top, to Commander Clement himself? Fortunately, the violence of space is a controlled violence, and determined men can slip through it with tools and building materials. They can base themselves on zero-gravity construction rafts and take refuge in pressurized crevices, go floating along steel girders five hundred feet in length until there has been assembled the greatest of all miracles--a manned Space Station a thousand feet in diameter encircling Earth at a distance of fifteen hundred miles. The Station had not been built in space, it had been built on Earth section by section. However, the final task of putting it together had been left to the floating men in their fishbowl helmets, the suicide brigade with their incredible vacuum equipment and remote control welding arms. Fifty-seven sections had been built on Earth over a period of five years, thirty-four in the Eastern United States, the rest in scattered localities from Chicago to the Gold Coast. They had all been sent up by step rockets into the same narrow orbit around Earth. They were fifty-seven sections "crash landing" in a total vacuum, weightless and yet with sufficient mass and inertia to keep them in close proximity until the great task could get under way. The assembled Station was cone-shaped, and it had been a colossal undertaking to keep it from developing stress defects over a third of its bulk during the early constructional stages. Under the guidance of experts, the problem had been solved, but at a tragic price.