These proceedings from the second conference on the Epidemiology of Aging sponsored by the National Institutes of Health indicate the direction of recent research and concern in this area. Attempts are made to formulate a definition of aging other than that of chronological age. A number of biomedical correlates of aging are addressed, including some predictors of longevity, as well as age-correlated diseases that constitute some major health problems for older people. The social and psychological correlates of aging are examined as two highly productive research areas in the field. Health care implications and problems of the aged are addressed according to demographic projections and morbidity estimates. A summary of recent advances is provided, and major research concerns regarding the problems of the aged are identified. (Author/KMF)