This book is a comprehensive, multi-authored work on the structure and function of the mammalian testis. The approach emphasizes gene expression, translation and production of specific gene products and the cellular and molecular regulation of these fundamental processes. Rather than provide aglobal survey of all aspects of male reproduction, this book stresses specific mechanisms that underscore the structure and function of the testis. It explains old and new concepts from a cellular and molecular perspective. This novel approach allows the authors to forge links between cell andmolecular biology and well-established aspects of spermatogenesis and steroidogenesis. The result is a well-focused, comprehensive, and synthetic analysis of testicular biology.