During the past 5 years, impressive progress has been made in understanding the etiopathogenesis of expeiimental and clinical diabetes. The rapid progress that has been made in the general field of immulogy has made possible new understanding regarding the role of the immune system in the pathogenesis of diabetes. The other two areas in which recent progress has been made in the field of diabetes include genetics and the role of infectious agent(s) in the etiopathogenesis of diabetes. Because of these recent developments, a vast amount of data has been accumulated and published in a number of metabolic, endocrine, immulogical, and general medicine journals. The purpose of this book is to consolidate all the available information and present it in its current state. In the present volume, I strive to bring together relevant contributions from leaders in the fields of immupathology, immubiology, and genetics. The advancing understanding has in several instances reached the point of clinical applica- tion. This volume encompasses the entire scope of modem immulogy of diabetes mellitus. This volume has been divided into two major parts, Experimental Diabetes and Clinical Diabetes. In the Experimental part are included chapters dealing with the structure and functions of insulin and the immune response to insulin. Spontaneous and experimentally induced models of type I diabetes mellitus are presented. The role of virus(es) in the etiology of experimental diabetes and the influence of sex on experi- mental diabetes are discussed. The transplantation of pancreas and islets is reviewed in detail.