Werner Theodor Otto Forssmann, a surgeon and urologist, was born on August 29, 1904, in Berlin, the only child of Julius Forssmann, a lawyer employed by a life insurance company, and Emmy Hindenberg. Forssmann's father died in World War I while young Forssmann was still a student in the Askanische Gymnasium. His mother worked as an office clerk and his grandmother took over the role of running the household. Forssmann's uncle, a doctor just outside of Berlin, became an influential force in his nephew's life, ultimately convincing Forssmann to pursue a career in medicine. In 1922, after graduating from the Gymnasium, Forssmann entered the Friedrich Wilhelm University in Berlin, passing the state examination in 1928. Forssmann's doctoral thesis on the effects of concentrated liver on pernicious anemia, a blood deficiency, marked the way for his later experiments. Together with a small group of fellow students, Forssmann experimented on himself, taking large doses...