During the past decade, there has been a major reconceptual ization of adulthood as a period characterized by predictable and sequential developmental stages. Researchers and theorists have attempted to chart the sequence of developmental stages that adults pass through with as much certainty as psychologists once described the terrible twos or the traumas of the adolescent identity crisis. This study provides a review and critique of the salient research and theory of adult development, focusing on the tendency of most researchers to eliminate every social and historical element from the study of the psychological lives of adults -- a tendency that is reflected in the considerable sex, class and race bias of the existing literature. Riegel's (1975, 1975, 1979) dialectical paradigm, which conceptualizes adult development changes as resulting from the interactive effect of inner-biological, individual-psychological, and cultural-sociological factors, will be offered as a compelling conceptual schema for the study of adult developmental transitions.