Part 1 Children in a changing world: children and social change the study of child development. Part 2 The beginning of life: our biological heritage prenatal development and birth. Part 3 Infancy: physical development during infancy cognitive and language development during infancy social and emotional development during infancy. Part 4 The preschool years: physical development during the preschool years cognitive and language development during the preschool years social and emotional development during the preschool years. Part 5 The middle childhood years: physical development during middle childhood cognitive development during middle childhood social and emotional development during middle childhood. Part 6 Adolescence: physical development during adolescence cognitive development during adolescence social and emotional development during adolescence.