This work reviews the basic concepts of immunology and introduces the reader to the latest findings on immunological aspects of diseases of the head and neck. In the past two decades, there has been an explosion of new knowledge in immunology. The contributors to this volume, all of whom have been active in clinical and basic research, describe how recent discoveries in immunology play an increasingly vital role in the understanding and care of patients with head and neck diseases. An important teaching tool for the resident in training and a valuable reference work for physicians in practice, this book will be of special interest to otolaryngologist-head and neck surgeons, surgical oncologists, pediatricians, allergists, rheumatologists and edu­ cators desiring an advanced text in the field. Jacques F. Poliquin, MD Allen F. Ryan, PhD Jeffrey P. Harris, MD, PhD INTRODUCTION Immunology has been traced back at least to 1000 AD. when the Chinese discovered that the inhalation of smallpox crusts had some value in prevention of the disease. However, immunology as a science has developed almost entirely within the last 100 years.