The advances in our knowledge and understanding of stem cells have fundamentally changed the way we see human biology and physiology, not to mention disease. It has become clear in recent years that not only are our bodies more plastic than previously thought, but the number and type of stem cells that play a role in the generation and regeneration of human tissue far exceed original expectations. In order to characterize stem cells, they must first be identified. Markers for many different stem cell populations have been elucidated, but challenges still remain. The papers presented in this booklet highlight these hurdles as well as discuss the potential applications for stem cells in disease therapy and regenerative medicine.