This dissertation analyzes the literary milieu and print culture of mid-nineteenth-century British radicalism and suggests that early Victorian fiction was significantly shaped by the imaginative prose and editorial journalism of popular protest movements. It traces the interplay between the underground press and canonical Victorian novelists through a series of key controversies, including debates about the empire, political economy and the New Poor Law, suffrage rights and Chartism, and the condition of women. Although social-problem novelists often adopted the guise of brave anthropologists entering an unknown subterranean world when they wrote about the working-classes, the cultural reality of social division was different, characterized on both sides as much by argument, contest, parody, and appropriation as by separation and ignorance. In particular, Elizabeth Gaskell's evocation of collective forms of self-help in Mary Barton, Harriet Martineau's satire of Cobbettite theories of history in Illustrations of Political Economy, and Charles Dickens's analysis of the connections between continental republicanism and British radicalism in A Tale of Two Cities each make clear that popular protest was more than a theme to be analyzed as part of the "condition of England." The transaction between the unstamped and radical press and reforming novelists was complex and contradictory, characterized at once by violent denunciations and significant borrowings. The dissertation stresses the experimental nature of radical fiction: its frequent refusal of narrative closure, its use of montage, and its syncretic appropriation of both respectable forms of middle-class fiction and the sensational and prurient genres of penny dreadfuls and stage melodrama. Chartist authors like Thomas Martin Wheeler and Ernest Jones revised novelistic conventions in order to narrate broad patterns of causation and change. These experiments, as much as any political manifesto, reveal the breadth of vision of popular protest movements. The collisions and intersections which took place between the two literary nations disclose a Victorian culture fractured, contested and dynamic.