From the late 17th through the late 19th century, nostalgia denoted a form of homesickness so extreme that it could sometimes be deadly. What Nostalgia Was unearths that history. Thomas Dodman traces the invention of nostalgia as a medical diagnosis in Basel, Switzerland, its spread through the European republic of letters and into Napoleon’s armies, its subsequent transformation from a medical term to a more expansive cultural concept, and its shift in meaning in the colonies, where Frenchmen worried about racial and cultural mixing came to view moderate homesickness as salutary. Thomas Dodman is an Assistant Professor in the Department of French. David Bell is a Professor of History at Princeton. Emmanuelle Saada is an Associate Professor of History and French at Columbia.