Science fiction writers have odd ways of looking at the universe, if you ask us. Twenty thousand years ago mankind spread out of Africa like a disease consuming the world. We've got records of the settlement of the Americas by Europeans, for goodness' sake! But Raymond F. Jones, here, finds the notion problematic. "Extensions of humanity from one area to another on a permanent basis are made by colonists. Men who do not expect to rotate, " he has one character tell another, "but come to live and establish homes. This is what we want on Serrengia. Humanity is preparing to make an extension of itself in the Universe. But more than this, there are limitations of time and distance in the establishment of bases, which cannot be overcome by any amount of training of personnel. Cycles of rotation and distances from home can be lengthened beyond the capacity of men to endure. It is only when they go out with no expectation of return that time and distance cease to control them.