Over the last few years, emerging biotechnologies related to the manipulation of mammalian gametes such as nuclear transfer and production of transgenic animals has increased exponentially. However, such technologies requires excellent source of low cost embryos. In vitro production (IVP) of embryos provides considerable economic and scientific advantages because of the possibilities for mass production of embryos for gene transfer, cloning, production of transgenes and for researches on embryonic stem cells. This book, utilizes some established protocols to explore the optimal experimental condition for in vitro production of embryos. Especial emphasis was given for exploitation of the large number of preantral follicles in the mammalian ovaries, which could produce large numbers of oocytes. This book should be useful for postgraduate students of veterinary and animal production and especially for professionals and researchers in animal reproductive biotechnology.