Book excerpt: Beyond Adolescence traces the lives of adolescents and youth from the late 1960s into the late seventies and early eighties. It is unusual because of the period of time in which the study took place, as well as because of the portion of the lifespan it covers - early adulthood. Concerned with understanding the role of problem behaviour in young adulthood and the factors that influence it, the study also traces outcomes on young adulthood of earlier involvements in problem behaviour, with an emphasis on personality and social environment. The research extends and tests the theoretical framework that guided the study - Problem Behaviour Theory - and shows its usefulness for understanding young adult problem behaviour and development.