Preface. On History and Historians. Theories of Acquired Immunity. The Royal Experiment on Immunity: 1721-1722. Cellular versus Humoral Immunity: Determinants and Consequences of an Epic Nineteenth-Century Battle. Theories of Antibody Formation. The Concept of Immunologic Specificity. Immunologic Specificity, Continued. Horror Autotoxicus: The Concept of Autoimmunity. The Donath-Landsteiner Autoantibody: The Incommensurable Languages of Immunological Dispute. Allergy and Immunopathology: The Price of Immunity. Anti-antibodies and Anti-idiotype Immunoregulation: 1899-1904. Transplantation and Immunogenetics. Magic Bullets and Poisoned Arrows: The Uses of Antibody. Appendix A: The Calendar of Immunologic Progress. Appendix B: Nobel Prize Highlights in Immunology. Appendix C: Biographical Dictionary. Glossary. Name Index. Subject Index.