For this edition, the rapid advance of immunology has necessitated a complete revision of the text with the addition of 230 new entries, many in the rapidly developing fields of cellular immunology and immunogenetics. Some old entries, not strictly immunological, have been dropped, but care has been taken to retain and revise all those likely to be of value to those reading the literature of the science. The breadth of the definitions makes this book more than a dictionary but, rather, a readable piece of literature on immunology for beginner or expert.