Birds are hosts to many parasites, internal and external. The parasites inevitably form a burden to the host bird and therefore may affect its ability to grow, survive, and reproduce; its behaviour; and the distribution and abundance of the whole species. In consequence, bird-parasite systems have attracted attention from diverse fields and the literature has been spread out in a wide range of specialized journals. The editors of this book have drawn together a comprehensive range of experts in the field to provide an invaluable reference of current work in bird-parasite interactions. The book is divided into four parts. The introduction provides the contemporary context of research in bird-parasite systems and presents case studies which combine theoretical concepts with experimental data. Subsequent parts focus on the ecology; behavioural responses; and the effect of parasitism on sexual selection.