The unnamed narrator tells us of his claustrophobic existence somewhere in rural Ireland, and of his relationship with the leech-like John Divney, who's taken over his dead parents' farm and refuses to leave. Divney hatches a plan to murder a local miser, Mathers, and steal his money, and the hapless narrator agrees.
After returning to the house of the dead-and-buried miser to retrieve the money box, the narrator encounters Mathers in a dirty old bathrobe sipping watered-down tea. The money box has disappeared, and needless to say the narrator can't really be asking the inexplicably-alive-or-maybe-undead Mathers where it is. So he goes to the local police station thinking he'll claim he's lost his (nonexistent) American gold watch, and get the policemen's help finding the money box instead. There are a pair of cartoonish policemen at the station, and they spend a lot of time blabbing about humans who are part-bicycle and bicycles that are part-human, declaring this or that an 'insoluble pancake.' They take the narrator through the woods and down an elevator into a subterranean complex they claim is eternity, which they've found via the cracks on a bedroom ceiling that just happen to form a map of the area. Down in eternity the narrator wishes for wealth, a bottle of the best whiskey, and a fine suit, all of which materialize, but then the policemen tell him he can't take it into the elevator or they'll all explode. And so on and so forth.
After the first two (thoroughly engrossing) chapters I found The Third Policeman quite a tough slog—much too much gratuitous bizarreness, and the footnotes drove me nuts—but looking back on it now I see it all makes perfect sense. I wish I could discuss the ending, but I don't want to spoil it for you. I'll just say that what once seemed clever now feels derivative, because Brian O'Nolan did it first.
I think I'll be including my favorite passage in each of my '100 great books' write-ups. From page 40 of The Third Policeman:
...A good road will have character and a certain air of destiny, an indefinable intimation that it is going somewhere, be it east or west, and not coming back from there. If you go with such a road, he thinks, it will give you pleasant travelling, fine sights at every corner and a gentle ease of peregrination that will persuade you that you are walking forever on falling ground.Next up (talk about a diverse assortment of titles!): Viktor Frankl's Man's Search for Meaning.