'Ella Maclane is dying to come to Baden-Baden', remarks a character in Henry James's novel Confidence. But there is a hitch: 'Her father and mother think it's improper - what do you call it - immoral.' From the 1840s until the 1870s German water resorts, and Baden-Baden ("Europe's summer capital") in particular, were among the most fashionable - and notorious - of Continental destinations, famed for fostering transient and transgressive modes of therapy, sociability and play. In this study, an original alloy of comparative criticism and cultural history, B.D. Morgan reads across genres and literary traditions to decode the nineteenth century's fascination with the spa - a 'cosmopolitan' space in an era of nationalisms - before exploring the "classic" watering place's curious fictional afterlives.