In July 1518 a terrifying and mysterious plague struck the medieval city of Strasbourg. Hundreds of men and women danced wildly, day after day, in the punishing summer heat. They did not want to dance, but could not stop. Throughout August and early September more and more were seized by the same terrible compulsion. By the time the epidemic subsided, heat and exhaustion had claimed an untold number of lives, leaving thousands bewildered and bereaved, and an enduring enigma for future generations. Drawing on fresh evidence, John Waller's account of the bizarre events of 1518 explains why Strasbourg's dancing plague took place. In doing so it leads us into a largely vanished world, evoking the sights, sounds, aromas, diseases and hardships, the fervent supernaturalism, and the desperate hedonism of the late medieval world.