Several conceptualizations and definitions of retirement have been proposed. One of them--the three-stage transition process--can be illustrated from studies in Israel: (1) leaving the old role; (2) going through the act of formal separation; and (3) adjusting to the new situation and role. Today's higher rate of survival into later years means that retirement can be extended into a period of 15-20 years during which three additional subtransitions may occur: onset of sickness and disability, institutionalization, and widowhood. The growing trend of early retirement causes a further extension of the retirement period through earlier entry into this role by relatively young old persons, widening the gap between retirement and traditional concepts of old age. Analysis of some research findings reveals conflicting role expectations and strain resulting from early transition into retirement status and role. It is tentatively suggested that three distinct substages emerge in the extended retirement period: pre-aging retirement (early retirement), active (engaged) retirement, and passive (stabilized) retirement, each with its own characteristics and needs. These developments require long-range planning, with both individuals and society adjusting to specific situations and needs as they arise. (KC)