The past two decades have seen rapid and fundamental advances in our knowledge of the basic science of immunology and how this relates to a better understanding of disease processes. The increasing complexity of immunology and its greater application to medicine has made it ever more important that students of medicine and science receive clear and careful explanation of this difficult subject. To help the student follow the developing themes, this edition has been restructured. The book is now divided into six sections which present immunology in a logical and progressive narrative.