Generally, antisocial behavior in the teenage years is preceded by childhood antisocial behavior and followed by adult antisocial behavior. The chapter has a developmental focus in studying why people begin to display different types of antisocial behavior, why they continue or escalate, and why they eventually stop or change to other types. It reviews important risk factors: high impulsivity and low intelligence; family influences such as poor child rearing and antisocial parents; peer influences; socioeconomic factors; and situational influences. The chapter also discusses protective factors and implications for preventive interventions; childhood behavioral precursors; adult behavioral sequelae; and antisocial careers. It is plausible to suggest that there is an antisocial personality that arises in childhood and persists into adulthood, with numerous different behavioral manifestations. About half of a sample of antisocial children go on to become antisocial teenagers, and about half of antisocial teenagers go on to become antisocial adults. References