The book highlights the therapeutic applications of various stem cells, and introduces readers to thymus stem cells and their applications in the reconstitution of thymic structure and function. It also discusses the significant role of mesenchymal stem cells (MSCs) in the treatment of autoimmune diseases and the use of MSC-derived exosomes in cell-free therapy. Moreover, it explores the application of hematopoietic stem cells in the vasculoprotection of the ischemially injured heart. Further topics include the regenerative potential of ovarian germline stem cells and the significance of endometrial stem cells in the pathogenesis of female reproductive tract diseases. Lastly, the book addresses stem cells from perinatal tissues and their immunoregulatory and differentiation potentials, and summarizes new strategies for targeting cancer stem cells to treat tumors.