George E. Vaillant, M.D., is a psychoanalyst and a research psychiatrist, one of the pioneers in the study of adult development. He is a professor at Harvard University and directed Harvard’s Study of Adult Development for thirty-five years. He is the author of Aging Well, Triumphs of Experience, and The Natural History of Alcoholism, and his 1977 book, Adaptation to Life, is a classic text in the study of adult development.