This is a paperback edition of a highly acclaimed study of English popular radicalism during the period between the anti-Jacobin government 'Terror' of the 1790s and the beginnings of Chartism. Challenging conventional distinctions between 'high' and 'low' culture, Iain McCalman brilliantly reveals the links between the political underworld and literary culture, poverty, crime, and prophetic religion. Drawing on information from spy reports and contemporary literature, the book traces for the first time the history of the underground revolutionary-republican grouping founded by the agrarian reformer, Thomas Spence. Challenging conventional distinctions between 'high' and 'low' culture, McCalman illuminates the darker, more populist sides of Romanticism. His underworld of ideas links the Shelleys to pornographer-revolutionaries and political blackmailers, millenarian prophecy to discourses of blasphemy, black revolution and saturnalian theatricality, and radical journalism to the Grub Street undergrowth of bawdy and pornography which sprang up in the opening years of Queen Victoria's reign. Radical Underworld broadens the conventional boundaries of popular politics and culture by illuminating a political underworld connected with poverty, crime, prophetic religion and literary culture. It is a model of cultural history and a major re-evaluation of its topic.