Physique and Delinquent Behavior: A Thirty-year Follow-Up of William H. Sheldon’s Varieties of Delinquent Youth is a progress report on the lives of 200 men. The men detailed in this book started as boys in the middle 1930s that included runaways, truants, and delinquents. They became adults during the fluid socioeconomic, political and cultural times in the Unites States. The book defines the psychiatric variables and presents brief biographies of these men. The authors then apply a statistical review of the careers of these men that included 20 cases in a normal group, 90 cases in a second-order psychopathic groups, 12 cases in a borderline psychopathy group, 11 cases in a first order psychopathy group, and 16 cases of alcoholism. The rest are also classified in other groups such as gynephrenosis, criminality, or medical insufficiency. The authors point that an increasing probability of gynephrenotic difficulty in men whose ratings diverge far from that of the male mean. The authors also note that the constitutional approach they applied can explain some complex relation between biology and sex-related behavior. This book is suitable for behavioral scientists, psychiatrists, psychologists, students and professors in the sciences of human behavior.