Is there a formula—some mix of love, work, and psychological adaptation—for a good life? For 72 years, researchers at Harvard have been examining this question, following 268 men who entered college in the late 1930s through war, career, marriage and divorce, parenthood and grandparenthood, and old age. Here, for the first time, a journalist gains access to the archive of one of the most comprehensive longitudinal studies in history. Its contents, as much literature as science, offer profound insight into the human condition—and into the brilliant, complex mind of the study’s longtime director, George Vaillant.