Brian O'Nolan (Irish: Brian Ó Nualláin) (5 October 1911 – 1 April 1966) was an Irish novelist, playwright and satirist regarded as a key figure in postmodern literature. Born in Strabane, County Tyrone, he is best known for English language novels such as At Swim-Two-Birds, and The Third Policeman (written under the nom de plume Flann O'Brien) as well as many satirical columns in The Irish Times and an Irish language novel An Béal Bocht (written under the name Myles na gCopaleen).

O'Nolan wrote prodigiously during his years as a student at University College Dublin where he was an active, and controversial, member of the well known Literary and Historical Society. He contributed to the student magazine Comhthrom Féinne (Fair Play) under various guises, in particular the pseudonym Brother Barnabas. Significantly, he composed a story during this same period entitled "Scenes in a Novel (probably posthumous) by Brother Barnabas", which anticipates many of the ideas and themes later to be found in his novel, At Swim-Two-Birds. In it, the putative author of the story finds himself in riotous conflict with his characters, who are determined to follow their own paths regardless of the author's design. For example, the villain of the story, one Carruthers McDaid, intended by the author as the lowest form of scoundrel, "meant to sink slowly to absolutely the last extremities of human degradation", instead ekes out a modest living selling cats to elderly ladies and becomes a covert churchgoer without the author's consent. Meanwhile, the story's hero, Shaun Svoolish, chooses a comfortable, bourgeois life rather than romance and heroics: