The definition and nature of human aggression are considered, and cultural, individual, and situational factors facilitating aggression are discussed. Factors influencing the development and maintenance of an individual's chronic level of aggressiveness are discussed, including the learning of aggression and aggression-related norms from parents, peers, and other models and the more impersonal models portrayed by the mass media. Next, situational factors associated with the learning and support of aggression are discussed. These include cultural factors such as the availability of weapons or exposure to unpunished aggressive models, individual variables such as emotional arousal or drug or alcohol use, and environmental factors that encourage or restrain aggression and violent criminal acts. The ways in which characteristics of the actor, consequences of the behavior, and environmental factors may be associated with aggression or nonaggression are delineated. Implications for reducing and controlling aggression are suggested, including the deterrent effects of the criminal justice system. Finally, strategies for the elimination of violence are delineated. Name and subject indexes and approximately 420 references.