The Black Death was the great watershed in medieval history. In this compact book, David Herlihy makes bold yet subtle and subversive inquiries that challenge historical thinking about this disastrous period. As in a finely tuned detective story, he upturns intriguing bits of epidemiological evidence. And, looking beyond the view of the Black Death as unmitigated catastrophe, Herlihy sees in it the birth of technological advance as societies struggled to create labor-saving devices in the wake of population losses. New evidence for the plague's role in the establishment of universities, the spread of Christianity, the dissemination of vernacular cultures, and even the rise of nationalism demonstrates that this cataclysmic event marked a true turning point in history.