This book lays out the principles of mechanistic comparative physiology in an ecological and evolutionary context. Somero and Hochachka are among the most eminent workers at this important interface between a number of fields. They have collaborated on two earlier books covering this subject, which were the definitive treatments of the subject, so although this book will be completely rewritten, and with a different title, it is de facto the third edition of an established classic of the advanced literature. The subject of evolutionary physiology has advanced considerably since their last book, and so this volume will be a rather more satisfying synthesis than could be written earlier.