This book is the first to present a comprehensive overview of parasitic birds and their hosts. Although the phenomenon has attracted the interest of naturalists and evolutionists since Darwin, only recently have researchers applied modern evolutionary theory and experimental methods to study the various adaptations related to brood parasitism. The work in this field is accelerating rapidly, and this volume collects work from the individuals and research groups around the world who have been responsible for nearly every major study in the last ten years. The papers present valuable summaries along with substantial new research, and the volume concludes with a review of important unsolved questions. The book is an invaluable resource on this fascinating topic, covering the remarkable sequences of adaptations and counter-adaptations, along with the perhaps even more remarkable cases where adaptations seem to be lacking.