For a long time, research on developmental issues in the biological and social sciences has been primarily concerned with the early stages of the lifespan, such as infancy and adolescence. More and more researchers have recently turned their attention to the problems of development and aging in the later periods of life. This volume, based on papers presented by the European Network on Longitudinal Studies on Individual Development, deals with success in the aging process. From a medical or public health viewpoint, successful aging consists of optimizing life expectancy while at the same time minimizing physical, psychological, and social morbidity. Achievement of successful aging requires that the onset of infirmity, on average, increases more rapidly than average life expectancy, compressing morbidity into a shorter period. Current behavioral and social research shows physical plasticity in seniors, strong associations between lifestyle and health, increasingly healthy lifestyles on a national basis, and decreasing incidence of chronic disease.