This chapter reviews 10 years of research into a developmental taxonomy of antisocial behavior that proposed two primary hypothetical prototypes: life-course-persistent versus adolescence-limited offenders. The taxonomic theory was fully articulated for the first time in a chapter written for the first edition of Developmental Psychopathology (Caspi & Moffitt, 1995). Therefore, it is particularly appropriate to review for the second edition the research published since then. According to the taxonomic theory, life-course-persistent offenders' antisocial behavior has its origins in neurodevelopmental processes; it begins in childhood and continues persistently thereafter. In contrast, adolescence-limited offenders' antisocial behavior has its origins in social processes; it begins in adolescence and desists in young adulthood. According to the theory, life 76course-persistent antisocial individuals are few, persistent, and pathological. Adolescence-limited antisocial individuals are common, relatively transient, and near normative (Moffitt, 1990, 1993, 1994, 1997, 2003).