Public health and aging is a developing field, standing between clinical geriatrics and the demography and epidemiology of aging. It has heretofore lacked a unified treatment or single framework. This text provides such a framework and offers a first synthesis of a burgeoning literature in geriatrics, gerontology, occupational therapy, epidemiology, demography, neuropsychology, rehabilitation medicine, social work, and public policy. Key concepts and tools that define the field of public health and aging such as cohort analysis, the lifetable, age-sex pyramids and risk stratification are presented. A synthesis of the most productive measures of healthy aging, also of "successful aging" and frailty; sample studies; and clinical trials that address the question of age, health, and healthy old age are also included.