It wasn't just immigrants that flooded into the City during the nineteenth century, but also yellow fever, smallpox, cholera, typhoid and tuberculosis. Kelly traces the struggle that finally brought the City's first permanent Board of Health to fight the epidemics that had killed thousands of New Yorkers. Plus we meet two medical heroes who saved hundreds of lives: Edward R. Squibb, who started at the Brooklyn Navy Yard in the 1840s and perfected the manufacture of ether as an anesthetic, and a living legend of surgery at NYU Langone Medical Center who changed heart and vascular surgery, Dr. Frank Spencer.