What if history, as we know it, had run another course? Touching on alternate histories of the future and the past, or uchronias, A Past of Possibilities encourages deeper consideration of watershed moments in the course of history. Wide-ranging in scope, it examines the Boxer Rebellion in China, the 1848 revolution in France, and the assassination of Archduke Franz Ferdinand in 1914, and integrates science fiction, history, historiography, sociology, anthropology, and film. In probing the genre of literature and history that is fascinated with hypotheticals surrounding key points in history, Quentin Deluermoz and Pierre Singaravélou reach beyond a mere reimagining of history, exploring the limits and potentials of the futures past. From the most bizarre fiction to serious scientific hypothesis, they provide a survey of the uses of counterfactual histories, methodological issues on the possible in social sciences, and practical proposals for using alternate histories in research and the wider public.