This book presents a detailed examination of the physical properties of proteins and their associations with solvents, ligands, and each other. Incorporating observations from his classic work on the thermodynamics of protein-protein and protein-ligand interactions, the internationally recognized author offers a complete conceptual and quantitative description of proteins and their associations. The book begins with an overview of basic thermodynamic principles and goes on to describe the covalent and noncovalent binding of single and multiple ligands and their effects on protein-protein associations. Discussions of protein-solvent interactions address issues including protein folding, membrane associations, and protein dynamics. Attention is given to the effect of temperature and pressure on protein structure, oligomerization, and ligand binding, as well as to ideas about the basis of biological specificity. Although experimental work is discussed throughout the text, the book is not technique oriented. Its theoretical framework is clear, general and easily understandable, making this an essential textbook for beginning graduate students in biological sciences, as well as a valuable reference for advanced researchers in industry and academia.