Paul Ehrlich's Receptor Immunology: The Magnificent Obsession comprises a comprehensive history and exciting analysis of the work of Paul Ehrlich, MD (1854-1915), one of the founding fathers of immunology. A clinician by training, his research marked him as a pioneer experimentalist in haematology, immunology, and chemotherapy. A 1908 Nobel Prize Laureate for Physiology or Medicine, he also discovered a cure for syphilis (Salvarsan) and propounded the side-chain theory in immunology. As a result of his work, he laid the groundwork for the first 50 years of immunology, including the selectionist theory of antibody formation, kinetics of primary and secondary antibody response, quantitative methods of measurement of antigens and antibody, and demonstration of passive transfer of immunity from mother to foetus. A significant contribution to the Ehrlich legacy that has shaped our current world, this work is an invaluable resource for immunologists, virologists, geneticists, molecular biologists, haematologists, and science historians.