Although much is known with respect to blood cell formation and function, many new concepts in the areas of the regulation of hematopoietic stem cell commitment and the subsequent survival, proliferation, and differentiation of progenitors have been elucidated in the last five years. Our understanding of the microenvironment where stem cells reside and commit to distinct blood types (the niche) has grown significantly in recent years. Furthermore, blood cells have been used as the key model system to study microRNA function and the role of microRNAs in the transformation of normal cells into cancer cells. The current volume Molecular Basis of Hematopoiesis, edited by Amittha Wickrema & Barbara Kee, provides the most recent developments in the area in addition to a chapter on the utilization of basic science knowledge for the treatment of blood diseases. Each chapter in this book has been written and edited by faculty in major academic and research institutions around the world, who are pushing the frontiers of research in this important area.