This summary presents findings from the Monitoring the Future project, which involves repeated cross-sectional surveys as well as panel studies of youth throughout the United States. The data showed both changes and continuities in drug use and other deviant behaviors. Discussion of the findings focuses on five broad themes: (1) consistencies across time in correlates of deviant behavior; (2) different secular trends in deviant behavior; (3) stability in individual patterns of drug use; (4) changes linked to marital status and living arrangements; and (5) additional age-linked changes in deviant behaviors. The study discusses the implications of these findings in the concluding section, which suggests that any comprehensive effort to explain the totality of deviance in adolescence and young adulthood will have to account for both general factors and those which are specific to particular deviant behaviors. References are included, along with a set of statistical charts that show relevant longitudinal findings from the study. (TE)