In the Preface to his volume on Ecophysiology of the Camelidae and Desert Ruminants in this series, Trevor Wilson mentions his hesitation at the invitation from John Cloudsley-Thompson to write the book, because he had been out of direct touch with desert biology for some years. My response to John''s invitation to write Ecophysiology of Desert Birds was much the same, and for the same reasons. However, with his encouragement and, taking account of the fact that a colleague of mine who is much better suited to do the job had turned it down because of pressure of work, I accepted the challenge and have enjoyed it immensely. It has been my privilege to spend much time in the deserts of North and South America, southern Africa and Australia, some of it with my wife, Cherie, whose editing of the entire text has improved the work immeasurably. Indeed, I believe it would have been proper for her to accept coauthorship, but she graciously declined the offer! I owe her a debt of gratitude which I hope will be repaid in part by her seeing the text finally between covers. The chapters on water regulation (Chap. 5) and thermo regulation (Chap. 6) have benefited from the refereeing of my colleague, Dr. Barry Lovegrove, of the Department of Zoology and Entomology, University of Natal, Pietermaritzburg.