Cooperative breeding refers to a social system in which individuals other than the parents provide care for the offspring. Since individuals delay breeding and invest in the offspring of others, cooperative breeding poses a challenge to a Darwinian explanation of the evolution of social behaviour. The contributors to this book explore the evolutionary, ecological, behavioural and physiological basis of cooperative breeding in mammals. The book contains a collection of chapters by the leading researchers in the field, and it is the first book dedicated exclusively to the study of mammalian cooperative breeding. It will appeal to zoologists, ecologists, evolutionary biologists, and to those interested in animal behaviour.