From the time of Hippocrates to that of Louis Pasteur, the medical profession relied on plausible but almost wholly mistaken ideas about the causes of and best treatments for infectious illness. Bleeding, purging, and mysterious nostrums remained staple remedies, and surgeons, often wearing filthy butcher's aprons, blithely spread infection from patient to patient. Then between 1879 and 1900 came the germ revolution. After two decades of scientific virtuosity, outstanding feats of intellectual courage, bitter personal rivalries, and a large dose of good fortune, doctors came to realize infectious diseases are caused by microscopic organisms. The discovery of the germ led to safe surgery, large-scale vaccination programs, dramatic improvements in hygiene and sanitation, and the pasteurization of dairy products. Above all, it set the stage for the emergence of antibiotic medicine.

John Waller provides insight into twenty years in the history of medicine that profoundly changed the way we view disease. He shows how the germ revolution was made possible not only by the risk taking and raw ambition of several brilliant late-century pioneers, but also by the groundwork—including mistakes and near misses—of earlier generations of scientists. Rich in human drama, The Discovery of the Germ charts how, why, and by whom germ theory was transformed from a hotly disputed speculation to a central tenet of modern medicine. It examines the ideas and experiments of the giants of microbiology, Louis Pasteur and Robert Koch, as well as less well known figures such as Casimir-Joseph Davaine, Waldemar Haffkine, and Almroth Wright.