The current book is from the Master’s work of Mr. Mahmoud M. Abdel Hamid. It describes in details the most dramatic histological changes of the rabbit testis during its descending Journey. It covers the period of the postnatal development starting from 0 day to 24 weeks. The testicular histology based on a light microscopic description of sections from paraffin and resin embedded was carefully provided. In addition, different testicular growth parameters including the testicular weight, length, breadth and thickness as well as diameter of seminiferous tubules, number of germ cells and Sertoli cells per seminiferous tubule were estimated during each stage of development. The position of the testis whether in the abdominal cavity, inguinal canal or in scrotum was recorded during its migration. The current results should be used as a baseline in other studies made on testis of other species including human.