The individual's attitude toward the Determiner of Destiny, which is religion, has always an essentially practical coloring. It involves a belief, to be sure, but this belief is never a matter of pure theory; it bears a reference, more or less explicit, to the fate of the individual's values. Hence in nearly every religion which history has studied or anthropology discovered, the question of the future in store for the individual believer has been one of prime importance. The content of this belief is a question for the theologian and the historian of religion; the psychologist, however, may be able to throw some light on the related question why people believe, or fail to believe, in immortality at all. What, in short, are the psychological sources from which this belief springs, and what are the leading types of this belief?