The distinction between aggression and abuse is highlighted by the different research approaches taken toward each. The prototypical studies on relationship abuse involve in-depth, qualitative, or clinical interview studies with battered women, while studies using the relationship aggression approach obtain data from national representative surveys of U.S. households that are based on an objective checklist of aggressive behaviors. This article summarizes empirical research findings relating to the prevalence of psychological aggression in marriage, associations with physical aggression, other correlates and presumed causes, gender differences, and effects of abuse. The authors make several policy-related recommendations: continue to increase public awareness of family violence through education and focused media campaigns, develop and promote relationship enhancement and early intervention programs, and stress the role of psychologically abusive behavior and tactics of power and control in intervention programs with batterers. 1 table, 1 figure, 7 notes, and 79 references