This paper is concerned with adaptation through time and with life time as differentiated from calendar or historical time. Life time is that of socially defined time; thus the author examines the system of social expectations regarding age-appropriate behavior which requires adaptive behavior on the part of adults. (SJL)

A systematic review and critique of the work of midlife researchers and theorists such as Gould, Vaillant, Jung, Newman and Levinson, among others, indicates that: (1) a midlife transition period exists from approximately 35 to 55 and lasts as many as 10 years for both men and women; (2) a series of unique and fundamental biological, psychosocial,…