Long before Covid and the West Nile virus, yellow fever was a medical mystery that forced thousands in Philadelphia, the nation’s temporary capital, to flee and brought the workings of the federal government to a virtual halt. A riveting account of this country’s first large-scale medical epidemic, is generously illustrated with archival prints and photographs and includes a bibliography, map, and index. This is the story of how half the city’s residents fled and half of those who remained died; neighboring towns, cities and states barricaded themselves; George Washington himself fled, setting off a constitutional crisis; and bloodletting caused blood to run through the streets. It is also the story of a little known chapter in Black history in which free Blacks nursed the sick only to be later condemned for their heroic efforts. Meticulously researched, first-hand accounts, newspaper clippings, death lists, and period engravings recreate the fear and panic while exploring the political, social, cultural, medical and scientific history of the times. A final chapter explores the causes of the epidemic and provides a wake-up call about the potential for epidemics today.