The Third Policeman is the second novel by Flann O’Brien, the pseudonym for Irish writer Brian O’Nolan, written in 1939/1940 but only published posthumously in 1967. It was originally rejected by the publishers of his acclaimed first novel, At Swim-Two-Birds (1939) and was largely forgotten until after his death. The novel is an absurdist, darkly comic novel narrated by an unnamed rural Irish “scholar” whose obsession with the eccentric thinker de Selby intersects with him committing a botched robbery and murder. The narrator’s flight leads into a surreal police barracks and an afterlife-like logic system where “Atomic Theory,” bicycles, and bureaucratic interrogation replace ordinary causality. The novel explores Unknowability as Part of the Human Experience, The Interchange Between Human and Machine, and The Agony of Banality and Bureaucracy.

A civil servant for much of his career, O’Brien was a key figure in Irish literary Modernism and Postmodernism, and wrote satirical journalism as well as fiction. The novel appeared in a 2005 episode of the popular television show Lost, with writer and producer Craig Wright suggesting that the book provided a key to understanding the show’s plot. In the three weeks after its appearance on the show, the book sold 15,000 copies—as many as had been sold in the previous six years. 

This guide uses the 2007 Harper Perennial Modern Classics print edition.

Content Warning: The source material and guide feature depictions of graphic violence and death.

Plot Summary

The novel is told by an unnamed narrator, who was raised on a farm with a public house in rural Ireland. After the deaths of his parents, he goes to an expensive boarding school. While there, he discovers the writer and philosopher de Selby, and becomes obsessed with studying and writing commentary on his works. He travels and breaks his leg, ending up with a wooden prosthetic. He returns home to meet John Divney, whom his father had employed to work the farm in his absence. While Divney says he will leave now that the narrator has returned, he never does. Several years later, Divney needs money to get married and the narrator needs funds to publish the work he has written about de Selby. Together, they murder a nearby landowner, old Mathers, when he is transporting funds to town in his money box. Divney disappears as the narrator is striking Mathers with his spade and hides the money box. He refuses to tell the narrator where it is for years until things quiet down, but finally tells the narrator he can go retrieve it from under the floorboards in Mathers’s own house. Although it is not revealed until the very end of the novel, Divney has actually hidden a bomb in the floorboards, which kills the narrator.

Not realizing what has happened, the narrator is surprised that he saw the money box, but then it disappeared. He looks up to find old Mathers in the house, and they have a conversation. Mathers mentions three policemen who have strange gifts and have been at their barracks nearby for hundreds of years. The narrator decides to go there to find out where the money box has gone. He leaves Mathers’s house the next morning and meets a robber on the road. While the man initially threatens to kill the narrator, he eventually introduces himself as Martin Finnucane, leader of the one-legged men, and they bond over the fact that they both have wooden prosthetics. Finnucane directs the narrator toward the police barracks.

The narrator arrives at the police barracks and meets Sergeant Pluck and MacCruiskeen, two of the policemen. The policemen talk obsessively about bicycles, insisting that the narrator must be there about a bicycle. They elaborate that almost all of the crime in the parish relates to bicycles. Another civilian, Mr. Gilhaney, arrives asking about his stolen bicycle. The Sergeant asks the narrator if he wants to go help in the search. They find the missing bicycle and the Sergeant admits to the narrator that he is the one who stole it. He explains that there is a problem in the parish: People are becoming part-bicycle and bicycles are becoming part-human.



An Inspector arrives at the station and begins talking about Mathers’s murder. The Sergeant says he already has the murderer in custody, and the narrator realizes it is him. The Sergeant says he will be hanged, but they need to build a scaffold for the job. In the meantime, the Sergeant shows the narrator a magical map on the ceiling of MacCruiskeen’s room that shows the way to eternity, via elevator. They walk down a lane, then travel down an elevator into a building with numerous wires, clocks, doors, and ovens. The Sergeant explains that there are “readings” and measurements in this eternity that they must watch and intervene if the numbers become too high. They return upward in the elevator and to the police barracks again. The narrator goes to sleep.

He wakes to the sound of hammering and a man building the scaffold for his hanging. He realizes the man looks like Finnucane, and he says he is almost related to the latter. The narrator writes a message asking for Finnucane’s help and asks the man to deliver it.

The sergeant receives a note from Policeman Fox, the third policeman, who is reportedly eccentric, cranky, and rarely seen. Fox says that the band of one-legged men are coming to rescue the prisoner. The Sergeant quickly prepares to hang the narrator, but is interrupted by MacCruiskeen. There is a high reading in “eternity” they must deal with. The Sergeant leaves. Exhausted, the narrator goes inside and falls asleep. MacCruiskeen returns alone, and tells the narrator the Sergeant and a group of newly deputized civilians are waiting to ambush the one-legged men. MacCruiskeen prepares to go attack them. As a weapon, MacCruiskeen uses paint in an incomprehensible color that caused Policeman Fox to lose his mind when he viewed it. He paints his bike with it and sets off to meet the band of one-legged men.

The narrator takes the Sergeant’s bicycle and escapes. He finds himself near home, at Mathers’s house. There, he meets the third policeman, Fox, who takes him to a police station inside the walls of Mathers’s house. He tells the narrator he found the money box, which contains a magical substance called “omnium” that can do anything, and that the box is back at the narrator’s own house. 

The narrator goes there and finds Divney, his wife, and his son. Divney has aged 16 years, and is terrified to see the narrator. He raves, dying, and admits that he killed the narrator by placing a bomb where the money box should be. The novel ends with a passage that describes the narrator approaching the police barracks. The prose is repeated almost exactly from the narrator’s first approach to the station much earlier in the novel. Divney, who has just died of fright at seeing the narrator, is now there as well, joining the narrator in the hell of repeated experience.