Werner Forssmann, André F. Cournand, and Dickinson W. Richards were awarded the Nobel Prize in 1956 for seminal work on heart catheterization, Forssmann for his pioneering self-experiment, and Cournand and Richards for establishing heart catheterization as a standard diagnostic and treatment procedure in cardiology. Forssmann's self-experiment pushed the boundaries of medicine into a new era and opened the door of modern cardiology. This historical study depicts Forssmann's life narrative and the forces, political and personal as well, that shaped his personality. His upbringing in Berlin, his career as a physician, the self-experiment, and his life as a Nobel Laureate will be reviewed. His preoccupation with euthanasia, and in the scientific community a rather unknown aspect of his intellectual productivity in his late life, will also be evaluated.