Description:This survey on the "state-of-the-science" of stem cell biology explains the origins of stem cells and describes how they function, how they can cause illness, and how they might be employed to cure or ameliorate disease. In particular, the authors discuss the roles of stem cells in development and organogenesis, in normal tissue turnover, in the repair response to injury, and in carcinogenesis. They also explain how to obtain stem cells from different organs, culture them in vitro, and manipulate them for therapeutic use.