Maccoby's book is beautifully written and organized. In the first half she takes us on a journey from infancy through pre-school behavior, to elementary school and adolescence. Fascinating evidence is adduced for the formation of sex-segregated social groups, which are amazingly resistant in middle childhood to well-meaning adult attempts to force integration. In the second half...issues of sex roles in the workplace and in parenthood are discussed. A variety of explanations for the seemingly universal existence of sex role differentiation are proposed, from biology to evolutionary psychology.