Stem cell biology is a rapidly growing research area that for many seems to have burst upon the scene only recently with the isolation of human embryonic stem cells and the discovery of somatic stem cells in a variety of adult organs. Yet the concept of stem cells has a long history, and the clinical use of somatic stem cells was initiated already half a century ago in the context of bone marrow transplantation. Based on personal recollections from my own research career, this short historical account of the formative years of haematopoiesis research will highlight some of the pioneers who recognized and proved the existence of bone marrow stem cells and paved the way for their use in the treatment of blood disorders