Stem cells are undifferentiated cells that can divide to create various types of cells. These cells can stay as stem cells, or can be designed to differentiate. Cellular differentiation is the process by which one cell type changes to another specialized cell type. Stem cells are the source of the specialized cells that make up the tissue and organs of animals and plants. Therapies using stem cells can be used to replace defective or damaged cells caused by several disorders such as Parkinson's disease, heart disease and diabetes. Embryonic stem cells and adult stem cells are the two major types of stem cells. The aim of this book is to present researches that have transformed stem cell research and aided its advancement. It presents researches and studies performed by experts across the globe. This book is a vital tool for all researching and studying this field.