Few diseases are more gruesome than typhus. Transmitted by body lice, it afflicts the dispossessed--refugees, soldiers, and ghettoized peoples--causing hallucinations, terrible headaches, boiling fever, and often death. The disease plagued the German army on the Eastern Front and left the Reich desperate for a vaccine. For this they turned to the brilliant and eccentric Polish zoologist Rudolf Weigl. In the 1920s, Weigl had created the first typhus...