"Watch those courtesy titles," Morgan reprimanded gently. "'Mister' comes ultimately from the Latin _magister_, meaning 'master' or 'teacher'. And while I may be your master, I wouldn't dare think I could teach you anything." "All citizens are entitled to be called 'Mister'," the manager said with a puzzled look. He pushed a room key across the desk. "Which just goes to show you," said Harry Morgan, picking up the key. He turned casually, took one or two steps away from the registration desk, then--quite suddenly--did an about-face and snapped: "_What happened to Jack Latrobe?_" "Who?" said the manager, his face gaping stupidly. Harry Morgan knew human beings, and he was fairly certain that the manager couldn't have reacted that way unless he honestly had no notion of what Morgan was talking about. He smiled sweetly. "Never you mind, dear boy. Thank you for the key." He turned again and headed for the elevator bank, confident that the manager would find the question he had asked about Jack Latrobe so completely meaningless as to be incapable of registering as a useful memory. He was perfectly right. III The Belt Cities could survive without the help of Earth, and the Supreme Congress of the United Nations of Earth knew it. But they also knew that "survive" did not by any means have the same semantic or factual content as "live comfortably". If Earth were to vanish overnight, the people of the Belt would live, but they would be seriously handicapped. On the other hand, the people of Earth could survive--as they had for millennia--without the Belt Cities, and while doing without Belt imports might be painful, it would by no means be deadly. But both the Belt Cities and the Earth knew that the destruction of one would mean the collapse of the other as a civilization. Earth needed iron. Belt iron was cheap. The big iron deposits of Earth were worked out, and the metal had been widely scattered. The removal of the asteroids as a cheap source would mean that iron would become prohibitively expensive. Without cheap iron, Earth's civilization would have to undergo a painfully drastic change--a collapse and regeneration. But the Belt Cities were handicapped by the fact that they had had as yet neither the time nor the resources to manufacture anything but absolute necessities. Cloth, for example, was imported from Earth. A society that is still busy struggling for the bare necessities--such as manufacturing its own air--has no time to build the huge looms necessary to weave cloth ... or to make clothes, except on a minor scale. Food? You can have hydroponic gardens on an asteroid, but raising beef cattle, even on Ceres, was difficult. Eventually, perhaps, but not yet. The Belt Cities were populated by pioneers who still had not given up the luxuries of civilization. Their one weakness was that they had their cake and were happily eating it, too.