"Up-Helly-Aa" is Europe's largest and most spectacular winter fire festival. In the biting Arctic wind on the last Tuesday of every January, a "Guizer Jarl" leads one thousand men in guising costumes with flaming torches through the streets of Lerwick, the capital of the Shetland Isles, accompanying a Viking galley to its ceremonial burning. This is a study of the historical origins and contemporary significance of "Up-Helly-Aa". It traces the formation of Yule celebrations in the 1840s, in which inebriated apprentices jousted with sledge-propelled flaming tar-barrels to the terror of the middle classes and the police, into the civic ritual constructed in the 1880s and the 1890s by Shetland nationalists, folk revivalists, labour activists, teetotallers and municiple authorities. In the 20th century, the renamed "Up-Helly-Aa" became the principal community event in the Shetlands, making complex statements about gender, class, "nation", rebelliousness and respectability, and acquiring political significance after 1979 with the discovery of North Sea oil and the rise of Scottish nationalism.