Organ transplantation is one of the major medical triumphs of the last fifty years. Today, surgeons routinely remove dying livers, kidneys, lungs, and heart and replace with healthy donated ones. Yet the triumph is not without its tragedies. Shortages of healthy organs, rejection of transplanted organs, and debilitating drugs have hampered progress. For these and other reasons, the future of organ transplants looks to animal, artificial, and genetically engineered solutions.