This book, conceived as an atlas with emphasis in diagnostic images, presents some tumors displaying expected clinical, histological or biological behavior but in most of them that differs from that usual morphology or clinical behaviour. About 132 tumors of the testicles and paratesticular structures have been selected, representing all the testicular and paratesticular tumor groups, including germinal, gonadal stromal, non-gonadal stromal, rete testis tumors, ovarian-type epithelial tumors, and epididymis, spermatic cord and testicular covers as well as metastatic tumors. The format with large number of images allows pathologists to identify the entities included at a glance. Each section corresponds to one case including a brief clinical history, a concise histological description with immunohistochemical techniques necessary to confirm the diagnosis. In addition, each section provides several sample images, with histological details of the appropriate morphological or characteristic immunoexpression of diagnostic markers and in the majority of cases gross or radiologic figures. Finally, each section ends with a comment on the problems of differential diagnosis that could arise. The book is intended for pathologists, urologists and oncologists.