List of Plates. -- Introduction by Sir Gustav Nossal. -- Preface. -- The Background to Ehrlich's Immunology: Origins of the Receptor Theory. -- On Ricin and Abrin: Quantitation Enters Immunity Research. -- The Value of Mother's Milk: The Founding of Pediatric Immunology. -- The Standardization of Toxins and Antitoxins. -- The Toxin-Antitoxin Reaction: Theory Outpaces Data. -- The Side-Chain Theory of Antibody Formation. -- Immune Hemolysis: Bordet Challenges Ehrlich. -- New Scientific Challenges. -- Ehrlich's Scientific Style. -- Appendix A. Paul Ehrlich's Honors. -- Appendix B. Paul Ehrlich's Scientific Bibliography. -- Name Index. -- Subject Index.