Male reproduction is one of the important traits in livestock that greatly influence the economy of any livestock business. But acute shortage of genetically superior bucks is one of the major constraints of goat production in Bangladesh. It is established that due to haphazard breeding system the genetic merit of Black Bengal goat is under threat. In this regard, superior buck selection seems to be very important and alternative approach to boast up the production potential. Therefore, during selection of breeding buck special attention should be given on age, body weight, soundness of the sexual organ especially testis and quality of semen. The testicular parenchyma is composed of seminiferous tubules (from which spermatozoa is formed) and leydig cells or interstitial cells. The sertoli cells are responsible for phagocytosis of residual cytoplasm cast off during maturation of spermatocytes and for synthesis of androgen-binding protein which is essential for proper germ cell differentiation and leydig cells secrete testosterone responsible for male sexuality. This book will enrich the knowledge regarding male reproduction.