Domestic violence is a serious public health concern in the United States. Despite the serious and often tragically fatal consequences of spousal abuse, we have very little understanding about the root causes of domestic violence. We know even less about providing effective treatments and prevention. In this article, we have discussed some of the more promising individual difference variables that discriminate between violent and nonviolent men. We also have addressed some of the growing research on how violent couples are different from nonviolent ones. Unfortunately, methodologic limitations hamper us from being able to discuss definitive risk factors or predictive variables, but we can speak of factors associated with domestic violence. We also have discussed the importance of attending to important differences among violent men and violent couples. The complexity of battering behavior and battering relationships necessarily points researchers and clinicians toward multifaceted research designs and treatment models. The tragedy of domestic violence demands that science continues to address these crucial unanswered questions.