This set of essays on the benefits of history for medical practice is the first of its kind. Twenty-three physicians, who are also accomplished historians, write autobiographically about how they use history in practicing medicine. Sometimes it suggests a brilliant diagnosis of effective treatment. At other times, it consoles and encourages, not with inspirational tales of discovery and triumph but with reminders of the timelessness of medical uncertainty, weariness, and despair. History also prescribes a sobering antidote for the arrogance that tracks life in medicine like an occupational hazard. The authors are from five countries and diverse specialties. Acclaimed writer and surgeon, Sherwin Nuland, describes the sudden presence of history in the operating room. Martensen, Bryan, and Cule each discover a stalwart ally when they confront terrifying new plagues. Psychiatrists Belkin and Braslow rely on history to comprehend difficult patients (and themselves). To pediatricians Markel, Baker, Schalick, and Shein and to nephrologists Moss, it exposes the transience of diseases, both new and old. Internists Crenner, Humphreys, and Moulin are guided by history through helplessness at the bedsides of the dying. Hematologist Duffin draws on archival sources to diagnose the blood and behavior of a mysterious blue nun. Comfortable with crossing boundaries of time, historical learning eases travel over other boundaries of culture, race and experience.