Cooperative breeding refers to a social system in which individuals other than the parents provide care for the offspring. In addition to alloparental care, two further characteristics are common among species exhibiting cooperative breeding: delayed dispersal and delayed reproduction. Among vertebrates, cooperative breeding is expressed most prominently in birds and mammals. The book explores the phenomenon in a wide variety of mammals, including rodents, primates, viverrids, and carnivores. Comparative studies of cooperative breeding provide important tests for the origin and maintenance of sociality in complex groups. Understanding the behavioral and physiological mechanisms underlying cooperative breeding yields insights into the fundamental building blocks of social behavior in animal societies. Although several recent volumes have summarized the state of our knowledge of the ecology and evolution of cooperative breeding in birds, Cooperative Breeding in Mammals is the first book devoted to these issues in mammals, and it will appeal to zoologists, ecologists, evolutionary biologists, and those interested in animal behavior.