With 76 colour plates, 405 colour photographs, 756 distribution maps, C. 8000 bibliographical references. Foreword by Nigel J. Collar. Introduction. Order STRIGIFORMES. Family TYTONIDAE (Barn-owls). Family STRIGIDAE (Typical Owls). Order CAPRIMULGIFORMES. Family STEATORNITHIDAE (Oilbird). Family AEGOTHELIDAE (Owlet-nightjars). Family PODARGIDAE (Frogmouths). Family NYCTIBIIDAE (Potoos). Family CAPRIMULGIDAE (Nightjars). Order APODIFORMES. Family APODIDAE (Swifts). Family HEMIPROCNIDAE (Tree-swifts). Family TROCHILIDAE (Hummingbirds). REFERENCES. References of Scientific Descriptions. General List of References.