A number of important advances have been made in testicular tumor pathology since the publication of the 2nd series fascicle, Tumors of the Male Genital System, necessitating a separate atlas devoted to the testis, its adnexa, spermatic cord, and scrotum to incorporate this new information. The publication of this work is timely, as the incidence of testicular cancer in many countries continues to increase. Because of the need for effective, yet different, therapeutic approaches for many entities, accurate pathologic interpretation of these tumors, most of which occur in young patients, is of paramount importance.This atlas emphasizes the differential diagnosis of testicular tumors. It begins with a consideration of general aspects, including epidemiology, followed by a discussion of the histogenesis of germ cell tumors, including the lesion known as ?intratubular germ cell neoplasia, unclassified type.? Typical seminoma is consid­ered and illustrated in detail, as well as variants such as tubular seminoma, seminoma with cribriform patterns, spermatocytic seminoma, and spermato-cytic seminoma with sarcoma. Also thoroughly covered are nonseminomatous germ cell tumors and sex cord-stromal tumors. An entire chapter is devoted to the many non-neoplastic lesions of this region that are, in some instances, easily misinterpreted as neoplastic. The final chapter is devoted to the scrotum. Newer diagnostic approaches, e.g., immunohistochemical and molecular analyses, are discussed as supplemental methods; however7, the emphasis of this work remains routine light-microscopic interpretation. Where appropriate, the diagnostic utility of ultrastructure is considered. In addition the clinical significance of each lesion is discussed. This 385-page atlas, written by three pathologists with extensive experience evaluat­ing testicular pathology includes 535 color and 42 halftone illustrations. Every effort has been made to include the most current references as well as important contributions from the older literature.