This is a comprehensive monograph dealing with all aspects of protein metabolism and nutrition in man and lower animal forms. It is composed of 15 chapters on special aspects of the subject written by authors who are well known for their research in the fields dealt with. In addition to basic considerations of protein chemistry, intermediary metabolism and the nutritional essentiality of certain amino acids, the all-important place of protein molecules in the fabrication of such vitally important substances as enzymes, hormones, antigens and immune bodies is clearly delineated.