Evolutionary psychology is defined as the attempt to understand normal social motives as products of the process of evolution by natural selection. Analyses of American data on killings among kinfolk, supported by statistics from other times and places, show that blood relationships are much less lethal than other intimate relationships. The book contrasts primitive cultures in which infanticide occurs and is legitimized with parental homicide in the modern West. Parricide is explained in terms of temporally shifting conflicts between parent and offspring instead of Freud's Oedipal theories. The book also examines violent altercations that arise from status competition and reasons why they involve men far more often than women. The role of male sexual proprietariness in homicidal violence is explored in the chapter on spousal killings. The final homicide motive considered is blood revenge, as seen in myths and throughout recorded history. Other subjects discussed include the insanity defense, sentencing practices, and cultural variations in homicide. Tables, bibliography, and index.