Stem cells are the cells which differentiate into other cells and thereby replenish tissues of the body. This gives them the potential for therapeutic use in tissue repair and regeneration. Stem cells can be categorized into distinct cell types- embryonic stem cells and adult stem cells. Embryonic stem cells can divide into more stem cells or any type of cell in the body. This allows embryonic stem cells to repair or regenerate diseased tissues and organs. Adult stem cells were believed to create only similar kinds of cells but emerging evidence suggests that these may also have the ability to create other types of cells. This holds immense potential in medicine. Adult stem cells are being tested in people with heart disease or neurological conditions. Adult cells have been successfully transformed into stem cells using genetic reprogramming. This can enable the use of reprogrammed cells and prevent the immune system rejection of new stem cells. This book discusses the fundamentals as well as modern approaches of stem cell therapy. It consists of contributions made by international experts. For all readers who are interested in the study of stem cells, the case studies included in this book will serve as an excellent guide to develop a comprehensive understanding.