Violent husbands evidence more psychological distress, more tendencies toward personality disorders, more attachment/dependency problems, more anger/hostility, and more alcohol problems than nonviolent men. They also evidence fewer social (e.g., communication) skills, particularly in marital interactions. The role of biological and physical factors has rarely been examined, but the available evidence suggests that at least some men who have head injuries are at risk for marital violence, and initial data suggest a possible role of testosterone. In addition, male batterers may hold attitudes toward violence and women and attributions regarding both wifely behavior and their own violence that increase their risk for using physical aggression. They may lack resources or feel powerless. Similarly, they may experience more individual stressors than other men, although the data on this variable are mixed. Such factors (e.g., feeling powerless or stressed) may interact with other variables to precipitate the use of violence. Maritally violent men are more likely than nonviolent husbands to have experienced violence in their family of origin. Finally, more recent trends in this research area suggest that various risk factors interact in complex ways to predict husband aggression. In addition, typology research suggests that comparing violent to nonviolent men on individual variables may be inappropriate given the heterogeneity within samples of violent husbands. The second article in this series will examine the effects of marital violence on battered women and their children, and the third article will review sociodemographic correlates of violence and the ways in which violent couples differ from nonviolent couples. 121 references