Flann O'Brien, born as Brian Ó Nualláin in Strabane, County Tyrone, is celebrated as a remarkable figure in the panorama of twentieth-century Irish literature. Best known through his pen name Flann O'Brien, he also wrote under the aliases Myles na Gopaleen and Brother Barnabas. His work, which includes novels, plays, and satirical columns, positioned him as a major influencer in both modernist and postmodern literature movements.

O'Brien's novels, notably At Swim-Two-Birds and The Third Policeman, encapsulate his unique brand of unconventional humour and are recognized as significant contributions to modernist metafiction. Although deeply influenced by James Joyce, O'Brien maintained a critical distance from the Joycean "cult", famously expressing his exasperation with the excessive adulation Joyce received.

His contributions weren't confined to English literature alone; his satirical columns in The Irish Times and his Irish-language novel An Béal Bocht were penned under the name Myles na Gopaleen, highlighting his versatility and command over both languages. O'Brien's legacy is not just that of a novelist but also that of a satirist who wielded his pen to critique and entertain, leaving an indelible mark on Irish literary culture.