Listen. I’ll tell you something about the best book in the world. The best book in the world is so good you can use it to refine your social life.

Take a copy of Irish author Flann O’Brien’s The Third Policeman: you can lend it to somebody you know, and based on their reaction to its contents, decide whether to accept them as a friend, downgrade them to an acquaintance, or, if they really don’t like it, drop them completely.

I have done this more than once, even with people I have known for some time.

The Third Policeman has the sort of qualities that any good friend should appreciate, and any rather tiresome or dull sort of comrade would not.

It is, from start to finish, funny. Like the very best literature, it is also abundantly dark. But it’s more than that. It has the sort of astounding absurdity that only the finest minds – the sort of mind one might demand of a chum – could produce and appreciate.

You can start to sort your world into people that share your fierce joy at Flann O’Brien’s brilliance, and those that don’t There is the ongoing obsession with bicycles throughout the best book in the world, but not a normal obsession. Bicycle clips, seats and lamps fascinate Flann O’Brien, but so does the matter of dissipated atoms from two-wheelers that result in the combining of bicycle and rider to the point their personalities mix and the country is beleaguered by half people and half bicycles.

Men who become more than half bicycle spend a lot of time leaning with one elbow against a wall or standing propped up by one foot on kerbstones.

There are the strange philosophies of de Selby – the footnotes on whom crowd out the text itself in parts – including his belief night-time is due to an accumulation of “black air’’ produced by certain volcanic activities.

There is the small army of one-legged men driven mad by a policeman on a bicycle of such a colour it unhinges the mind. There is no end to the zealously deranged inventiveness. And the author and publication of The Third Policeman, both tinged with just the right amount of literary tragedy, only add to the exceptional level of gratification the book can provide the reader with the wherewithal to appreciate it.

O’Brien was one of the many pseudonyms of Brian O’Nolan, the fifth of 12 children, born in County Tyrone in 1911. In 1935 he joined the Irish Civil Service , and was private secretary to successive ministers for Local Government until he retired in 1953. In 1940 he began a celebrated satirical column for the The Irish Times under the pseudonym Myles na Gopaleen, the pseudonym required because civil servants were not allowed to publish under their real names.

He was, it appears, an alcoholic. Not only that, but there is a unique little tragedy associated with The Third Policeman: despite its glaringly obvious and untrammeled brilliance, it was turned down by publishers. O’Brien withdrew the manuscript, which he wrote in 1939-40, from circulation, and claimed he had lost it.

He died in 1966, and the book was published posthumously in 1967. That failure adds the most gratifying, bitter poignancy to the whole experience.

What is The Third Policeman about? It’s about a murder. The narrator begins with a statement that makes that clear. “Not everybody knows how I killed old Phillip Mathers, smashing his jaw in with my spade.’’ The murder and its bizarre antecedents begin the story, and the narrative’s strangeness only ramps up after the deed is done.

The narrator finds himself in a rural Ireland where, for instance, skewed laws of physics and absurdities of perception means he can see the front and back of a building at the same time.

There is so much more, perversely strange, fiendishly weird and endlessly oddly dark, which at its best produces deep sighs as you take in your own lack of creative excellence in the face of such mastery of divine madness. But you can read it yourself.

Then you can start to sort your world into people that share your fierce joy at Flann O’Brien’s brilliance, and those that don’t. The latter group you can cast adrift, perhaps by email, or perhaps by sending them a strongly worded letter in a stamped envelope withdrawing your emotional support. Because those people should be no longer your friends. They just don’t get the sort of literary brilliance that any good friend should appreciate.

Best they be downgraded to acquaintances.