Stem cells are the cells that differentiate into other cells and divide upon self-renewal to produce more stem cells. There are two types of stem cells, embryonic stem cells and adult stem cells. Progenitor cells and stem cells serve as a repair system by replenishing adult tissues. In the developing embryo, stem cells differentiate into specialized cells- endoderm, ectoderm and mesoderm, and also maintain the normal turnover of regenerative organs like skin, blood and intestinal tissues. Embryonic stem cells are a theoretically potential source for the development of regenerative medicine and tissue replacement. Adult stem cells can be acquired from adipose tissue, blood and bone marrow, as well as from the blood of the umbilical cord after birth. They are used in medical therapies such as in bone marrow transplantation. They can also be artificially grown and differentiated into specialized cells. Stem cell therapy helps to treat and prevent diseases or conditions. Some of the diseases where stem cell treatment holds potential include Parkinson's disease, diabetes, osteoarthritis, spinal cord injury repair, rheumatoid arthritis, cancer, amyotrophic lateral sclerosis, etc. This book is a valuable compilation of topics, ranging from the basic to the most complex advances in stem cells. It explores all the important aspects of stem cell therapy in the present day scenario. Scientists and students actively engaged in this field will find this book full of crucial and unexplored concepts.