During the past decade extensive investigations have been done on the testis. Since the observations have been published in many different journals. it seemed appropriate to bring together and summarize some of the pertinent findings in a single volume. Twenty-eight scientists and clinicians from nine countries have contributed to this book. They have reviewed the literature and presented their own, new observations on the developmentaL anatomicaL physiologicaL biochemical and pathological aspects of the descended and cryptorchid testis. In addition, several contributors have evaluated the usefulness of certain animals as models for systematically studying specific aspects of cryptorchidism. It is hoped that this volume will serve as