Hiro Nakauchi obtained a M.D. from Yokohama City University School of Medicine and a Ph.D. in immunology from University of Tokyo Graduate School of Medicine. He isolated CD8 genes during his post-doc period at the Laboratory of Prof. Leonard Herzenberg at Stanford University. After returning to Japan, he started working on hematopoietic stem cells in his laboratory at RIKEN. In 1994, he became Professor of Immunology at the University of Tsukuba where he demonstrated that a single hematopoietic stem cell could reconstitute the entire hematopoietic system, a definitive experimental proof for the “stemness”. Since April 2002, he has been a Professor of Stem Cell Therapy in the Institute of Medical Science at The University of Tokyo (IMSUT). In 2008, he was appointed Director of newly established Center for Stem Cell Biology and Regenerative Medicine at IMSUT. Just recently, he returned to Stanford University as a faculty to continue his stem cell research at the Institute of Stem Cell Biology and Regenerative Medicine. Goals of his work are to translate discoveries in basic research into practical medical applications.