This book presents two unpublished plays by the English radical, John Thelwall (1764-1834), who, as a leading member of the prorevolutionary London Corresponding Society, was tried and acquitted of high treason in 1794. A close friend of Coleridge, Thelwall was a prolific man of letters who produced novels, poetry, journalism, criticism, scientific and political essays, and autobiography. Both plays, libretti for the London theater, are especially topical today as popular literary forms to polemicize critical issues of race, empire, revolution, and sexuality. Incle and Yarico (1787) comically treats the well-known eighteenth-century love story of Inkle and Yarico, in which an English merchant betrays and sells into slavery an Indian maiden, and innocent ‘Noble Savage.’ The play may well be the earliest drama penned specifically in the cause of abolition. The Incas (1792) allegorizes the French Revolution and the English suppression of dissent in portraying a confrontation between the Europeans and the New World. Drawing upon and extending the precepts of Enlightenment radicalism, Thelwall undermines the justifications for empire. These manuscript plays, recovered from library archives at Yale University and the British Library, add to the growing canon of an author whose reputation continues to be augmented by new discoveries and fresh insights. In separate introductions and explanatory notes, the editors contextualize each play in terms of the London theater, the slave trade controversy, representations of race, and opposition to empire.