The underlying theme of this book is the biology of oxygen. The 22 chapters cover aspects of molecular, cellular, and integrative physiological functions. A fundamental evolutionary feature of the oxygen-consuming organism is that it developed a oxygen-sensing mechanism as apart of feedback control at the levels of molecules, organelles, organs, and systems. Oxygen sensing is partic ularly expressed in certain specific cells and tissues like peripheral chemore ceptors, erythroprotein-producing cells, and vascular smooth muscle. Apart of the book is focused on the current issues of this basic question of chemosen sing. Mitrochondria as the major site for cellular oxygen consumption is a nat ural candidate for cellular oxygen sensitivity and adaptation. A section deals with this question. A perennial question concerns chronic environment al oxy gen and the organism''s response and adaptation to it. This theme runs through several chapters. Because comparative physiology often provides insight into the mechanisms of environment al adaptation, a chapter on respiration of high altitude birds has been incorporated. Obviously this book gives only glimpses of the immense field of oxygen biology. The book grew out of two meetings where these subjects were discussed. These meetings were sponsored by the American Physiological Society and the Federation of American Societies for Experimental Biology. We are grateful to the FASEB Program Committee and APS publication committee for their sup port. We owe much to Ms. Anne Miller for her editorial assistance. S. L. Philadelphia N. S . C. Cleveland R. S. F.
