Question: What novel written by an Irish novelist, playwright and satirist,  who wrote under the pseudonym Flann O'Brien, was published by MacGibbon & Kee in 1967?
Context: The Hard Life: An Exegesis of Squalor is a comic novel by Flann O'Brien (pen name of Brian O'Nolan).  Published in 1961, it was O'Brien's fourth novel and the third to be published.  (He wrote "The Third Policeman" in 1939, but it was published only posthumously, in 1967).  Set in turn-of-the-century Dublin, "The Hard Life" is a satirical Bildungsroman that deals with the education and upbringing of the narrator, Finbarr, and his brother Manus.  The novel offers a mocking critique of certain representatives of the Roman Catholic Church, the development of Irish identity and the functioning of formal education.  The novel was initially very popular, with its first print run selling out within forty-eight hours (p. 271), and it has been republished several times in Ireland, Britain and the United States, both as a stand-alone work and, most recently, in "Flann O'Brien: The Complete Novels" (Everyman's Library, 2007). The Light of the Evening is a 2006 novel by Irish novelist Edna O'Brien.  The novel explores the relationship between one of O'Brien's archetypal defeated rural women, who on her deathbed is trying repair her relationship with her daughter, a writer. House of Splendid Isolation is a 1994 novel by Irish novelist Edna O'Brien.  The novel depicts the relations of an Irish Republican Army terrorist and his hostage, an elderly woman.  The novel blends an attempt at thriller, with O'Brien's deep exploration of Irish society.  Reception of the novel was not very good, especially in comparison to O'Brien's previous novels. The High Road is a 1988 novel by Irish novelist Edna O'Brien.  The novel follows an unnamed Irish protagonist as she recovers on a Mediterranean island.  It was O'Brien's tenth novel, published 11 years after "Johnny I Hardly Knew You." Brian O'Nolan (Irish: "Brian Ó Nualláin" ; 5 October 1911 – 1 April 1966) was an Irish novelist, playwright and satirist, considered a major figure in twentieth century Irish literature.  Born in Strabane, County Tyrone, he is regarded as a key figure in postmodern literature.  His English language novels, such as "At Swim-Two-Birds", and "The Third Policeman", were written under the "pen name" Flann O'Brien.  His many satirical columns in "The Irish Times" and an Irish language novel "An Béal Bocht" were written under the name Myles na gCopaleen. Poor Cow is the first full-length novel by Nell Dunn, first published in 1967 by MacGibbon & Kee.  The novel is a study of a working class girl from the East End of London, struggling through the swinging sixties after making one bad decision too many.  The novel was adapted for film in the same year of publication. An Béal Bocht (Irish: "The Poor Mouth" ) is a 1941 novel in Irish by Brian O'Nolan (Flann O'Brien), published under the pseudonym "Myles na gCopaleen".  It is widely regarded as one of the greatest Irish-language novels of the 20th century.  An English translation by Patrick C. Power appeared in 1973.  Stan Gebler Davies wrote: ""The Poor Mouth" is wildly funny, but there is at the same time always a sense of black evil.  Only O'Brien's genius, of all the writers I can think of, was capable of that mixture of qualities." The Third Policeman is a novel by Irish writer Brian O'Nolan, writing under the pseudonym Flann O'Brien.  It was written between 1939 and 1940, but after it initially failed to find a publisher, the author withdrew the manuscript from circulation and claimed he had lost it.  The book remained unpublished at the time of his death in 1966.  It was published by MacGibbon & Kee in 1967. At Swim-Two-Birds is a 1939 novel by Irish writer Brian O'Nolan, writing under the pseudonym Flann O'Brien.  It is widely considered to be O'Brien's masterpiece, and one of the most sophisticated examples of metafiction. Peter Cunningham is an award-winning Irish novelist and newspaper columnist.  He grew up in Waterford and was educated at Waterpark School, Glenstal Abbey School and University College Dublin.  He worked as an accountant and a trader of commodities until 1986 when his first novel was published.  Titled 'Noble Lord', it was a thriller, written under the pseudonym Peter Lauder.  Later under the pseudonym Peter Wilben he published the Joe Grace Thriller Series.
Answer: The Third Policeman