The Proteins: Composition, Structure, and Function, Second Edition, Volume I explores the quantitative relationships between protein composition, structure, and function. This book is composed of six chapters that cover the rapid and fundamental advances in understanding protein chemistry. This book outlines first the quantitative procedures and various methods suitable for the determination of amino acids found as constituents of naturally occurring peptides and as free amino acids in tissues and body fluids. These topics are followed by a discussion on some of the aspects of peptide chemistry, which appear significant in relation to peptides possessing physiological activity. The next chapter considers protein synthesis that represents the sequences of chemical reactions whereby amino acids are assembled in biological systems to produce proteins. This volume also examines the correlation of structure with function; the mechanisms of control of protein biosynthesis; the exact role of intramolecular interactions in the determination of tertiary structure; and the colinearity of genetic “maps” with amino acid sequences. A chapter describes the methods of analysis and reactions of sulfhydryl, disulfide, and thiol ester groups in proteins, as well as the evidence relating to the functions of these sulfur groups in proteins. The final chapter looks into the models and theories for the noncovalent bond interactions in proteins. This book is of value to organic chemists, biochemists, and researchers in the protein-related fields.