Tall, thin Don Quixote is full of deluded imaginings, believing himself to be a knight-errant riding out to restore the bygone values of the age of chivalry. His comic foil Sancho Panza is short, fat, and ignorant, who, although aware of Quixote’s delusions, lets himself be caught up in his companion’s pursuit of honour and glory, albeit because he thinks he might get some personal gain from their adventures. Theirs is a sunny kind of frenmity, with Sancho as the comic sidekick, an everyman realist to his master’s idealist, spouting what have come to be called sanchismos, a humorous mixture of ironic Spanish proverbs and put-downs.

Waiting for Godot or, Frenemies: A Love Story. Two bowler-hatted old men wait by a leafless tree, much as they waited the day before, and as they will doubtless wait the next day, too. In Beckett’s play, there’s all the time in the world to occupy – time for old jokes and pratfalls, for bickering and recriminations, for nostalgia and wistfulness; anything “to hold the terrible silence at bay”. Vladimir, the more philosophical of the two, tends to muse on abstract matters; Estragon, the more mundane, is more concerned with the whereabouts of his next meal. But they are united in the push and pull of their frenmity, as their waiting threatens to erode all hope.

In The Loser, Bernhard presents his fictionalised Glenn Gould as the very embodiment of the great artist, which makes life very difficult, and, in the end, impossible, for Wertheimer, a fellow piano student at the Mozarteum in Salzburg. Wertheimer gives up his studies for good when he overhears Gould’s terrifyingly great rendition of Bach’s Goldberg Variations. But it is when Gould casually labels his friend a “loser” that Wertheimer is sent into a vortex of self-loathing, and, eventually, suicide.

Lawrence’s Women in Love is also a novel about men in love, and, indeed, in love with one another. Rupert Birkin, the central male character, has an evangelical sense that he must reckon with “the problem of love and eternal conjunction between two men”. His nude wrestling match with Gerald Crich, so memorably staged by Oliver Reed and Alan Bates in Ken Russell’s film, is a homoerotic tableau of the frenemy, with both men struggling at once for and against one another.

In Crash, when James Ballard is hospitalised after a car accident, he finds himself drawn into the orbit of a sinister former scientist, Robert Vaughan, who is obsessed with re-staging the car crashes of celebrities. Vaughan frightens Ballard even as he fascinates him, and their increasingly uneasy friendship tips over into something macabre. When Vaughan takes his last death drive, Ballard writes his hagiography, paying an ambivalent tribute to this Lucifer of the motorway.

Set in a sanatorium in Davos, in the decade leading up to the first world war, The Magic Mountain features a microcosm of the pre-war European intelligentsia, including the frenemies Lodovico Settembrini and Leo Naphta, the former embodying the positive, hopeful ideal of the Enlightenment, and the latter, the more chaotic, order-threatening aspects of fascism, anarchism and communism. The two men debate furiously, and end up fighting an improbable duel, foreshadowing the coming clash of ideologies that would tear the continent apart.

Neil Gaiman and Gene Wolfe…

Gene Wolfe’s epic science fiction series The Book of the New Sun has its share of mysteries. One of them is the strange friendship between Baldanders, the permanently exhausted giant who won’t stop growing, and the wily, diminutive Dr Talos who beats, bullies and cajoles his larger companion. Initially, the seemingly slow-witted giant appears to be Talos’s charge, but things turn out to be the other way around: Baldanders is actually a scientist allied with sinister alien forces, who built his frenemy Talos for obscurely masochistic purposes of his own.

Patricia Highsmith is a master of the perverse friendship, and her first novel Strangers on a Train was no exception. Hitchcock’s film version portrays Bruno as merrily murderous and Guy as morally upstanding, but the novel presents the two men intertwined in a twisted friendship that is more significant than any other in their lives. Guy may be disgusted by the drunken, vicious Bruno, but when Bruno falls overboard at sea, Guy instantly dives into the waves, unable to imagine life alone without his cruel friend.

In Humboldt’s Gift, Charles Citrine makes a fortune from writing a successful Broadway play, based on the life of his older friend, the poet Von Humboldt Fleisher. Big mistake! Although his manic depression, alcoholism and pill-popping mean that he’s never delivered on his early talent, Humboldt still upholds the loftiest ambitions for art – ambitions, which, he claims, Citrine has utterly betrayed. Citrine’s success means that the easy friendship this pair enjoyed has gone, with Humboldt wounding his now frenemy with accusations of sell-out and crass commercialism.

Stoppard famously sets Rosencrantz and Guildenstern Are Dead in the interstices of Hamlet, elevating two supporting characters from Shakespeare’s play into leads. His focus is on how the pair occupy themselves when they are offstage in the parent play, which appears to be by aimless banter and mock-philosophical arguments. But there’s an existential twist: Stoppard’s characters seem to be aware that they are unimportant fictional characters, each casting aspersions on the other’s comparative degree of reality, each claiming that the other doesn’t really exist. Such acts of frenmity grant them what little sense of reality they have in a world which seems, to them, to be absurd and out-of-control.