“Ian Stewart’s history of the idea of Celticism since the eighteenth century is imaginative, erudite, original, and continually surprising. Under his sympathetic but forensic interrogation, few Celt-related assumptions about ancestral identities, archaeology, linguistic patterns, nationalism, and racial theory emerge unaltered. Among much else, he reinterprets the histories of European high culture and the ‘Irish Question,’ rescues forgotten theorists such as E. E. Fournier d’Albe and cultural enterprises like fin de siècle pan-Celtcisim, and pursues the implications of this resilient but ambiguous concept for us today. A tour de force of scholarship and intellectual verve.”—Roy Foster, University of Oxford

“Stewart’s powerful and engaging book, with its cast of hundreds, reveals how simplified our histories of the Celts have been—and how culturally circumscribed. Packed with fascinating examples and rich in insights, this is a genuinely energizing quest for the Celts through time.”—Mary-Ann Constantine, author of Curious Travellers: Writing the Welsh Tour, 1760–1820

“The Celts is that rare thing—a book that is genuinely pathbreaking. Ian Stewart has written the definitive study of modern European ideas of the Celts—ideas that have been mobilized in the service of a multitude of political, cultural, and intellectual purposes, from nationalism and race theory to pan-Celtic revivalism. No one has attempted anything like this before, and Stewart succeeds triumphantly, offering an illuminating, sometimes disturbing, but always interesting account of a concept that for all its familiarity and significance remains imperfectly understood. Anyone who wants to understand how people and places came to be seen as ‘Celtic’ needs to read this book.”—Paul Readman, author of Storied Ground: Landscape and the Shaping of English National Identity

“An enormously erudite yet accessible account of a shapeshifting concept. Ian Stewart reminds us that Celticism was an international phenomenon and significantly interwoven with major European developments: the Enlightenment, revolution, nationalism, and the ‘science’ of race.”—Colin Kidd, University of St. Andrews