Having recently published A History of Transplantation Immunology, I have become acutely aware of the great revolution that has taken place in the field of organ transplantation - not only in terms of our understanding of the immunobiological mechanisms underlying the rejection process and the various means of prolonging graft survival, but also in clinical terms. Only 50 years ago, clinical kidney allo-transplantation (and it was the kidney that spearheaded clinical advances) was a highly experimental and dangerous procedure dependent on whole-body irradiation and the results were often intensely disappointing. Now, the transplantation of kidneys is almost routine, results are excellent and the lessons learnt about immunosuppression and patient management have been applied with great success to a large number of other organs (see below).