In both the United States and the Western world, violence seems to have increased steadily over the past several decades and to have become more vicious, impersonal, and almost random. An atmosphere of fearful concern about violence pervades the general public and conditions lives and social behavior in ways inconceivable to earlier generations. Demographic and economic changes have changed the causes of violence. In addition, changing social norms have meant, for example, that acts which were considered ordinary in one era have become a reportable assault in another. Nevertheless, the incidence of violent offenses among discharged patients is much less than that among the nonpatient population. Most surveys of civil and criminal violence show that under 20 percent of violent acts are associated with a diagnosable mental illness of either a psychotic or neurotic type. Among school children prone to violence, the most commonly diagnosed disorder is the attention deficit disorder with hyperactivity. Although learning disorders show no causal link to juvenile delinquency, half of adjudicated juvenile delinquents have a history of learning disability. Another large group of children and youths involved in violence have conduct disorders, including antisocial personalities and impulse disorders. Characteristics of nonpsychotic patients prone to violence are intense affect, hostility or depression, impulsivity, manipulativeness, and regressive childish behavior. Numerous studies provide data on the incidence and prevalence of mental disorders among the population of those who commit offenses. Data indicate that for any given individual, it is almost impossible to predict violent behavior out of context, yet these predictions are often made. Overall, violence among patients in the community is a community and social problem as much as it is a psychiatric and legal problem. Relatively effective modes of treatment are available when cooperation is secured. However, the majority of violent offenders, like the majority of violent nonoffenders, have no diagnosable mental disorder and never become patients. The violence of our society is part of its mores, values, and way of life. Twenty-one references are listed.