Data are from a longitudinal study of maltreated and nonmaltreated children assessed as preschoolers and again at school age. The dependent variable is the child's teacher's rating of aggression at school age. The independent variables are from preschool and school age observations of the mother-child interaction and the mother's report of physical discipline practices. The study suggests three independent but interrelated processes that lead to and sustain early childhood aggression. The first concerns resources for parenting. Parents who are more affluent are more likely to have experienced positive parenting themselves, to have sufficient skills and resources to cope with stressors, and to have access to social and economic buffers. The second process is the child's experience of nurturance, which is the foundation for his or her view of the world. A child's experience of harsh, negative interactions and a lack of nurturance will generate a feeling of vulnerability and of anger, resulting in a search for ways to protect oneself in a family that is unfeeling, hostile, and punitive. The third process concerns how the child relates to others. The positively nurtured and protected child is more likely to find satisfaction in interacting with similarly nonaggressive others. Children with a negative view of their family, the world, and themselves perceive aggressive behavior as affording protection and a way to exert control over others' disliked and threatening behavior. Consequently, it becomes an important feature of the children's interactions with others. Figures, table, references