This text uses a case-study approach to present core principles of biochemistry and molecular biology in the context of human disease. The thirty-three cases have been carefully chosen to cover key concepts and common diseases. Each chapter provides a specific patient report that includes relevant history, pertinent clinical laboratory data, physical findings, and subsequent diagnosis. This is followed by a comprehensive discussion of normal biochemical processes and reactions pertaining to the case, along with the pathophysiological mechanisms of the disease. In this third edition of the book, a new co-editor has aided in the substantially revised and more targeted selection of cases. The whole volume is now clearly focused on intermediary metabolism and other topics central to biochemistry. There are new chapters on topics such as collagen structure, mitochondrial metabolism, and hyperhomocysteinemia and vascular disease. There is also more coverage of nutritional biochemistry, including new chapters on protein-calorie malnutrition, obesity, vitamin A deficiency, and iron metabolism. The best cases were retained from the previous edition, and have been completely rewritten and updated to include recent advances in diagnostic biochemistry and the status of current therapies. Although the first edition was intended primarily for medical students, through the years the book has proven useful for a wide variety of students interested in the health science professions.