The history of blood transfusion is a fabulous human adventure in the course of which intentional and fortuitous conjunction of medical and scientific know-how resulted in the birth of a new medical discipline. The extraordinary revelation of these successive stages in which applied research predominated was the unsuspected potential of blood and bone marrow cells. This potential extends to a great number of pathologies, many of which are outside the field of hematology. Pursuing the development of this therapeutic potential is the challenge to be taken up in the next decade. No matter what complex technologies are called into play to this purpose, the donor remains the essential actor as he has been since the beginning of this story. Therefore, continued medical and scientific progress in this field must go hand in hand with unrelenting ethical reflection.