The aims of this book are to provide a synthesis of our current understanding of hemoglobin structure, function, and evolution, and to illustrate how research on this paradigmatic protein has provided general insights into mechanisms of molecular evolution and biochemical adaptation. The book promotes an appreciation of how mechanistic insights into protein function can enrich our understanding of how evolution works and, reciprocally, it highlights how approaches in evolutionary genetics (such as phylogenetic comparative methods and ancestral sequence reconstruction) can be brought to bear on questions about the functional evolution of proteins. This treatise on the functional evolution of hemoglobin illustrates how research on a single, well-chosen model system can enhance our investigative acuity and bring key conceptual questions into sharp focus. Hemoglobin: Insights into Protein Structure, Function, and Evolution is suitable for a wide range of graduate level students taking interdisciplinary courses in biochemical physiology and protein evolution, and will serve as a key reference for researchers in molecular evolution, biochemistry, and comparative physiology.