Innate immunity now forms the foundation of the discussion of the physiological basis of immunological systems, and in the section on antigen recognition, B- and T-cells are treated in parallel. While dealing with the acquired immune response, a large new section looks at lympho-proliferative disorders arising as unregulated cell development, and in the chapters on immunity to infection, a more expansive treatment of immunodeficiency has been included. The treatment of autoimmunity has been restructured, and includes an account of recent developments in the understanding of the pathogenesis of rheumatoid arthritis. This revised reprint of the sixth edition contains new diagrams and additions to the text, as well as an expanded coverage of AIDS.