Immunology is a rapidly developing subject. The contributors in this book present some components of immunological knowledge which relate to the present and the possible future practice of surgery. Aspects of cellular and humoral immunity necessary for understanding are described and considera­ tion given to the mechanisms underlying immunological diseases. Whilst the original interest in immune response was related to microbial resistance, the recent impetus to surgical immunology has been the resurgence of organ grafting. Separate sections of the book deal with clinical organ transplanta­ tion, the allograft reaction, graft rejection and immunogenetics. A pre-requi­ site of successful organ grafting is suppressive control of immune responses. Approaches to conventional immunosuppression and specific non-reactivity are therefore considered. One method of cancer therapy is strengthening of the host's immune responses. Both experimental and clinical immunotherapy are discussed and components of tumour immunology necessary for their rational understand­ ing are dealt with separately. Successful immunotherapy requires monitoring of immune responses but another method for improving results of cancer treatment is earlier diagnosis by immunological methods. The book is aimed at practising surgeons who want to know the relevance of immunology to clinical surgery and laboratory scientists needing to understand the applications of their basic concepts. I am very grateful both to the authors for their contributions and the editorial staff of MTP Press Limited, for their considerable help.