This textbook uses a case-study approach to present the core principles of biochemistry and molecular biology in the context of human disease to students who will be involved in patient care. The 29 clinical cases have been carefully selected to cover key scientific concepts and some common, and other not so common, diseases. While the principal focus is on topics relating to metabolic disease, further subjects such as connective tissue disorders, neurological disorders, auto-inflammatory disorders, infective diseases, and cancer are also addressed. Each chapter provides a specific patient report that includes the natural history, pertinent clinical laboratory data, physical findings, subsequent diagnosis, and therapy. This is followed by a comprehensive discussion of the normal biochemical processes and reactions pertaining to the case, along with the pathophysiological mechanisms of the disease. Graphical diagrams are provided in each chapter for ease of comprehension.