This book features selected aspects of the molecular endocrinology of the testis with specific emphasis on signal transduction and gene regulation. Each chapter is written by internationally recognized authorities. Covering both basic research and clinical andrology, the book presents subjects as hormonal gene regulation and post-meiotic gene expression. Molecular endocrinology and pathophysiology of GnRH deficiency and the LH and FSH receptors are presented. Components of cyclic nucleotide-dependent signalling systems are discussed. Furthermore, regulation and pathophysiology of steroidogenesis and androgen action are presented, as well as tyrosine kinase-mediated signalling in germ cells and sperm. Finally, researach in andrology and novel methods for in vitro fertilization are discussed.