Vivien Thomas was a pioneer whose genius in cardiac surgery changed the medical world—without ever holding a medical degree. Born in 1910 in New Iberia, Louisiana, and raised in Nashville, Tennessee, Thomas dreamed of becoming a doctor. But as a Black man in the Jim Crow era, financial and racial barriers blocked his path. A chance job as a lab assistant for Dr. Alfred Blalock at Vanderbilt University set his fate in motion. Despite having no formal medical training, Thomas quickly became Blaloc