Every age has evolved its mythology. In recent times the popularity of detective stories and sagas of cowboys and Indians has been equaled or exceeded by science fiction. Comparison of these myths indicates that the dazzling speed of technological innovation in the present generation has psychological effects to which the rapidly increasing vogue of science fiction may give some tentative clues. In an age in which mechanical 'brains', satellites, and flights to other planets exist, or are impending realities, the fantasies of science fiction are vehicles for expression of far greater anxieties and more deeply regressive defenses even than those which evoked the demigods, devils, and witches of other times.