This volume develops a comprehensive multivariate paradigm of the process of aging, delineating the factors underlying age-related degeneration. The model is aimed at understanding the conditions under which age sets into motion a process of degeneration. Accumulating evidence suggests that age per se is not the decisive factor in age-related regression--leading scholars to distinguish between chronological and functional age. The process of degeneration is evidently due to the combined impact of deleterious biophysiological, psychological, and socio-cultural factors and the interaction among them. Based on this evidence, Zeev Ben-Sira shows how age-related degeneration can be viewed as a product of a damaging cycle of reciprocally activating stimuli from the person's internal and external environment. Consequently, aging is conceptualized as a process of bio-psychosocial regression. The paradigm outlined in this volume identifies factors that are likely to accelerate or decelerate the process of aging.