Flann O'Brien was the best known pen name of Brian O'Nolan one of modern Ireland’s most perplexing, subversive and underrated writers. This new study assesses the whole span of O'Nolan’s achievement, including his early forays into public satire and his fabrication of authorial identities. Re-reading the whole span of Flann O'Brien’s work, this title reintroduces O'Brien as a figure more relevant than ever to contemporary debates in Modernism and Irish studies.