The stem cell century presents our society with a variety of complex and controversial policy challenges in addition to those we face in the realm of science and technology .Stem cells are cells that have the ability to divide for indefinite periods in culture and to give rise to specialized cells. The pursuit and production of knowledge through scientific research is an undertaking that offers enormous intellectual rewards for researchers while also performing an important social function. The advancement of science has transformed our lives in ways that would have been unpredictable just a half-century ago. Whether stem cell research will have a similar effect remains to be determined, but the promise is so great that it seems wise to consider seriously how best to further such research in a manner that is sensitive to public sensibilities. Public conversations about research and use of human stem cells are well underway. This book is intended to contribute to and inform this ongoing dialogue and hopes to offer an approach that balances the promise of human stem cell research in a manner that will lead to a consensus on how best to proceed for future use.