The cells that can divide in self-renewal to produce more of the same type of stem cells and differentiate into other types of cells are known as stem cells. There are two broad types of stem cells in mammals - embryonic stem cells and adult stem cells. The embryonic stem cells are isolated from the inner cell mass of blastocysts in early embryonic development. Adult stem cells are found in various tissues in fully developed mammals. Stem cells and progenitor cells act as a repair system for the body. Embryonic stem cells can differentiate into all the specialized cells in a developing embryo including endoderm, ectoderm and mesoderm. They also play an important role in maintaining the normal turnover of regenerative organs like intestinal tissues, blood and skin. The topics covered in this extensive book deal with the core aspects of stem cell biology. While understanding the long-term perspectives of the topics, it makes an effort in highlighting their impact as a modern tool for the growth of the discipline. Those with an interest in this field would find this book helpful.