The possibility of altering the course of Parkinson's disease by brain grafting is slowly becoming a reality through the efforts of many research groups worldwide. It has been shown that this procedure, as performed in high-level medical research centers, usually produces no permanent adverse effects and can effectively ameliorate parkinsonian signs in certain patients. This progress has served to reinforce our commitment to develop neural transplantation into an effective therapy to treat such a devastating neurodegenerative disease. We have summarized the most important events that have shaped the initial phase of this research. In the course of the last 4 years, considerable knowledge has been gained in the clinical neurosciences regarding the real potential of various brain grafting procedures in treating Parkinson's disease, their shortcomings, and their usefulness in carefully selected patients. There is still no consensus regarding the various fundamental aspects of human brain grafting in Parkinson's disease. Questions concerning surgical technique, candidate selection, the optimal brain regions for implantation, the optimal tissue for implantation, and the real usefulness of brain grafting must be addressed. The importance of the quality of adrenal medulla fragments for grafting, the requirement for immunosuppressors in fetal brain grafting, and the optimal fetal age and the amount of donor tissue for effective grafting are additional areas of concern. The potential of xenografting, preserved tissues, and genetically engineered cells for human brain grafting remain unanswered. The development of human neural transplantation is the responsibility and privilege of neurosurgery.