This book is intended to educate the primary health care provider about sexually transmitted and related diseases as they present in homosexually active men. But why a book discussing sexually transmitted diseases (STDs) in this population only? Surely STDs are not limited to homosexual males. The relatively high rates of incidence of many of these diseases among homosexually active men, however, and the large number of associated diagnostic and treatment problems have necessitated the collection into one volume of the information that is par­ ticularly relevant to the primary health care of this population. A book dealing with current trends in the diagnosis and treatment of sexual diseases can, by nature of the task, be neither encyclopedic nor all-encompassing. In this volume, the choice of disease entities and the amount of material included on each are based on consideration of the amount of current information and the relative degree of uniqueness of a given problem in homosexual men, rather than the absolute frequency of the disease. There is, therefore, a considerable amount of material on hepatitis B and gonococcal infections, reflecting the recent explosion of research and clinical investigation in these two areas. In contrast, little is said about nonspecific urethritis, chancroid, and lymphogranuloma ve­ nereum. In the case of nonspecific urethritis, although it is extremely common in homosexual men, little progress has been made in diagnosis or therapy.