Criminological research has emphasized the strong relationship between age and crime, with involvement in most crimes peaking in adolescence and then declining. However, there is also evidence of the early onset of delinquency and of the stability of criminal and deviant behavior over the life course. In this essay we reconcile these findings by synthesizing and integrating longitudinal research on childhood antisocial behavior, adolescent delinquency, and adult crime with theory and research on the life course. Consistent with a life-course perspective, we focus on continuities and discontinuities in deviant behavior over time and on the social influences of age-graded transitions and salient life events. Furthermore, we critically assess the implications of stability and change for longitudinal research. We conclude with an emerging research agenda for studying the relationship of crime and deviance with a broad range of social phenomena (e .g. occupational attainment, opportunity structures, marital attachment) over the life course.