If a man from the mid-1920s had picked up today's paper he would have mistaken it for a science fiction magazine. In the same way, if a man from the mid-1960s could be confronted with a national daily from thirty years hence he would shake his head and regard the whole thing as preposterous. Stop. Think. Wonder. Tomorrow's commonplace was today's miracle. Today's commonplace was yesterday's miracle. Most things change. Some change faster than others. Human nature changes most slowly of all. The sword has given way to the gun, but the hand that holds the gun is neither braver nor more cowardly than the hand that held the sword. The gun gives place to the heat ray and the energy blaster, but the hand still belongs to a hero or a coward. The greatest drama of the world is human drama. People are still fundamentally people. Spacemen are people. They will still have our human problems a hundred years hence. This is a story of people in the future facing our basic problems in a more complex environment.