Visitors to the Blalock Building at the Johns Hopkins University Medical Center are greeted by portraits of two great men. One, of renowned heart surgeon Alfred Blalock, speaks for itself. The other, of highschool graduate Vivien Thomas, is testimony to the incredible genius and determination of the first black man to hold a professional position at one of America's premier medical institutions.

Thomas's dreams of attending medical school were dashed when the Depression hit. After spending some time as a carpenter's apprentice, Thomas took what he expected to be a temporary job as a...