Aggression is viewed as part of a continuum with violence on the extreme end, encompassing destructive results as well as aggressive intent. Biological theories view violence as biologically determined. One such perspective sees aggression as a fighting instinct common to man and animals. Neuropsychological perspectives posit roles of hormones, heredity, and brain disorders in violent behavior. However, neuropsychologists note that such physiologic mechanisms are not the sole factors governing the incidence of aggressive behaviors. Psychologists have posited some affective conditions under which violence is more likely to occur. Low self-esteem, emotional deprivation, problems in interpersonal relationships, poorly developed ego functions, and frustrated goals can all be seen as predispositions to violent behaviors. Another determinant of violence, learning, has been examined in detail by social learning theorists. Evidence shows that aggression can be learned, but the exact behavioral response to that learning cannot be predicted in individuals. While factors such as cultural attitudes, structural violence in society, social disorganization, population density, poverty, and participation in a violent subculture tend to accompany violence, they do not lead to violence in all people who experience them. Both sociological and anthropological studies have shown the importance of cultural sanctions for violence. Comparisons of relatively violent and nonviolent cultures have afforded clues concerning societal practices related to aggressive behavior. A synthesis of theories is a necessary background for understanding and approaching violence in the family. A total of 240 chapter notes are given.