This book reviews the various metabolic and functional mechanisms that animals possess in order to successfully live in their own particular, often unique, environments. The book's purpose is to demonstrate both the diversity of responses that are shown (be they biochemical, physiological, or behavioral) and to demonstrate the underlying principles of gas exchange and transport for a wide range of diverse organisms. What results is a useful review and analysis of our modern understanding of the respiratory physiology of helminths (parasitic worms), crustacea, amphibians, reptiles, birds, and mammals. The approach taken by the editors is essentially comparative and the individual authors were chosen so as to provide a useful, complementary view of the subject.