The usefulness of a theory depends upon its ability to explain the present and predict the future. In this chapter, I shall simplify and elaborate, in a discursive way, the “disengagement” theory of aging that Henry and I developed with our colleagues between 1957 and 1960 (1,2). I hope in this way to make it better able to describe and predict both the range and the limits of the aging process. In its original form, the theory was too simple; it had only enough detail to account for the main outlines of the process of growing old. By adding new elements and elaborating the basic propositions in more detail, I hope to be able to suggest a little of the complexity and diversity that we see among men and women in old age.