More and more people live into old age. This demographic revolution underscores the fact that old age is the last uncharted and unattended phase of the life cycle. We know that old age is the last uncharted and unattended phase of the life cycle. We know very little about the strengths and weaknesses of old age or how to achieve a good balance between gains and losses, a meaningful conclusion to life. The fourth volume in a series sponsored by the European Science Foundation Network on Longitudinal Studies on Individual Development, Successful Aging presents in its first section general overviews on successful aging from psychological, sociological, and medical perspectives. The volume's second part focuses on selected areas of human functioning, such as intelligence, memory, athletics, life satisfaction, personal control, coping with illness and loss, widowhood, and mental health. The authors of the various chapters share in the view that aging is not identical with fate, but that individuals play a major role in designing their own process of aging.