The central questions of child social development bear upon the essential nature of human existence, including the lasting importance of the infant’s first social relationships, the stability of human personality, nature-nurture, the way to properly socialize children to be moral and successful, and the importance of family and friends. Social development research has broad relevance to issues in education, public policy, prevention, social work, and the life sciences. In this overview, we begin with some basic information on source material, history, and common journals in the field. Then comes coverage of critical issues in the child’s early social development: attachment to a loving adult, the importance of temperament, the study of genetic and other biological factors in development, and the relationship between ontogeny (the development of the individual) and phylogeny (the development of the species). Next comes a focus on some key behaviors that are seen as essential for successful socialization: moral and prosocial behavior, the motivation to achieve, and (the lack of) aggressive and antisocial behavior. We consider classic and recent research on the role of gender, ethnicity, and intergroup relations on children’s development as children learn to be part of a larger society. Finally comes research on two critical domains of influence in children’s social development: families and peers. The field of children’s social development is vibrant, exciting, and increasingly interconnected with other areas in prevention, education, and the biological and social sciences.