Amphibians and reptiles are successful organisms, and their ectothermal approach to terrestrial vertebrate life is quite different from the endothermal lifestyle of birds and mammals. The internal processes of ectotherms differ in many respects from the corresponding processes in endotherms, and amphibians and reptiles function differently from birds and mammals in communities and ecosystems. Understanding how and why amphibians and reptiles differ from birds and mammals enriches a biological education, and the study of herpetology is a great deal more than just the study of amphibians and reptiles. In our view, understanding amphibians and reptiles as organisms requires a perspective that integrates their morphology, physiology, behavior, and ecology and places that information in a phylogenetic context. This book does that--it presents the biology of amphibians and reptiles as the product of phylogenetic history and environmental influences acting in both ecological and evolutionary time. We emphasize how amphibians and reptiles function in the broadest sense. For example, ectothermal temperature regulation is reflected in nearly every aspect of the biology of amphibians and reptiles, from their body shapes (extremely small body size and elongate body shape are feasible only for ectotherms) to their role in ecosystems (low-energy flow and high-conversion efficiency are the result of ectothermy). We have emphasized the integration of information from different biological specialties to produce a picture of amphibians and reptiles as animals that do remarkable things and play important roles in modern ecosystems. Evolution provides the context in which the distinctive characteristics of amphibians and reptiles must be evaluated, and both ancestral and derived features are central to understanding their biology. Throughout the book we have emphasized the use of phylogenetic information to understand the evolution of ecological, behavioral, and physiological characters. This edition ofHerpetologyreflects both the rate of new developments in the discipline and the continuing contributions of colleagues who have suggested ways to expand and strengthen our treatment of the biology of amphibians and reptiles. The increasing use of cladistic techniques and the incorporation of more kinds of data in phylogenetic analyses have substantially changed our understanding of the history and content of some groups. Those changes are conspicuous in the chapters covering systematics and in the integration of phylogenetic information with studies of natural history. The addition of color photographs of many species provides a far better impression of the appearance of the animals and enhances the presentation of phenomena such as aposematic coloration and mimicry that lose much of their impact in blackand-white photographs. In response to suggestions from colleagues and students, we have added a chapter on biogeography to illustrate the important contributions that studies of amphibians and reptiles have made to this area and the insights about the ecology and evolution of extant species that only a biogeographic perspective can provide. Splitting the treatment of reproduction and life history into separate chapters--devoted to amphibians and to reptiles--has allowed us to respond to requests that we increase the amount of information about these important topics, and emphasize the major differences between the groups. And the expanded treatment of conservation in this edition reflects the importance this topic is assuming in many herpetology courses as habitat destruction, pollution, and disease exact an ever-increasing toll on the diversity of amphibians and reptiles. Collaboration by the six authors--whose research specializations include autecology, synecology, systematics, evolution, morphology, physiology, and behavior--has produced a treatment that interweaves these areasPough, F. Harvey is the author of 'Herpetology', published 2003 under ISBN 9780131008496 and ISBN 0131008498.