This work is a follow-up and companion volume to The North American Bird Guide. It looks in detail at all aspects of bird behaviour, ecology, taxonomy and conservation, considering each of the 80 American bird families in turn. The introductory sections cover ecological and biological concepts such as anatomy, aerodynamics, evolution, migration, habitats and population dynamics. The volume is illustrated throughout with David Sibley's artwork, and the text, from a team of 44 authors, draws on a variety of ornithological experience.