Today's most groundbreaking experiments in medicine gene editing to correct inherited disorders, immunotherapies to cure cancer, molecularly engineered organs for human transplantation stem from the strides of one visionary Dr. E. Donnall Thomas. In the last half of the twentieth century, Thomas himself discovered a cure for every marrow-based disease, like leukemia, lymphoma, and sickle-cell anemia, forever changing treatment for some of the deadliest illnesses. His feats were extraordinary, earning him a Nobel Prize, and the cascade of treatments he inspired have reshaped and will continue to reshape the practice of clinical medicine. Yet no one has ever written Thomas's courageous story.