It's the most prestigious writing prize in the English language. Previous winners are a roll call of literary giants from the past 40 years - VS Naipaul, Iris Murdoch, JM Coetzee, Ian McEwan, Margaret Atwood. And as much as these authors' book sales are dwarfed by those from thriller, fantasy or crime writers, the Man Booker Prize is increasingly important. Amid all the noise that surrounds publishing these days, readers appreciate guidance towards not just a good book, but a great one. Perhaps that's why last year's winner, Hilary Mantel's Wolf Hall, has now sold more than half a million copies in the UK alone. Aravind Adiga's The White Tiger, The Man Booker Prize Winner in 2008, hasn't fared too badly either.
This year's longlist - 13 books that stretched from Christos Tsiolkas's tale of a suburban barbecue gone spectacularly wrong to David Mitchell's historical fable The Thousand Autumns Of Jacob De Zoet - was the strongest in years, so there was always going to be an element of controversy when it was finally whittled down to the six shortlisted books on Tuesday. However, to find both Tsiolkas - something of a beach read hit - and the literary pyrotechnics of Mitchell omitted was something of a surprise.
Still, the chairman of judges Andrew Motion said the six "outstanding" novels - by Peter Carey, Emma Donoghue, Damon Galgut, Howard Jacobson, Andrea Levy and Tom McCarthy - were "books that demonstrate a rich variety of styles and themes - while in every case providing deep individual pleasures". That means everything from Jewish comedy to a novel inspired by the Josef Fritzl case - and some of the books listed play with the form of the novel completely. None more so than Tom McCarthy's C. The notion of a book, which, as Luke Kennard wrote in The National last month, is "both a troubling enigma and a migraine-inducing sprawl" is hardly enticing. But McCarthy's third book, which explores the emergence of technology at the beginning of the 20th century through the life of Serge Carrefax, throbs with odd connections and resonances. Such an "explosion of information", as described in The National, is both maddening and hugely exciting - and if there's one book on this list that might have been a "chairman's pick", you sense it was C. (Judge Motion, of course, was the former Poet Laureate, so it helps that McCarthy's book reads like a long poem).
If that sounds odd, Damon Galgut's In A Strange Room might not even be a novel at all. Taking the form of three stories of journeys that Galgut made - to Greece, India and Africa - it operates on the boundaries between memory and fiction, exploring what is true and imagined. Written mainly in the third person but often flitting to the first - sometimes even in the same sentence - it's a brilliant author who manages to make such a device work. But it's not a stunt; rather, Galgut's voice is both comically nihilistic and horrifically disillusioned.
Galgut and McCarthy represent the experimental arm of literary fiction, but even the most obviously best-selling author on the shortlist wasn't afraid to make her readers work harder for their enjoyment. Andrea Levy, whose Small Island was a massive critical and commercial success in 2004, tells the story of a 19th-century Jamaican girl, July, in The Long Song. Ostensibly, the book tracks July's life through the turbulent years before and after the abolition of slavery. But the narrative often stops abruptly to chart the fortunes of her son, Thomas, who wants to publish his mother's memoirs. Much of the comedy - for all the horrors of slavery, this is an enjoyable book - comes from these passages, when Thomas refuses to countenance the way July is telling her story. I reviewed this in February, noting that The Long Song crackles with ambition. Though Levy doesn't always transfer that to coherent storytelling, it's certainly one of the most readable novels here.
Staying firmly in centuries past, Peter Carey's Parrot And Olivierin America is an inventive and somewhat eccentric story of a French aristocrat who travels to the New World with his servant. Cleverly, the narrative shifts between the two men's perspectives while the whole notion of America is created in front of our eyes. Gaiutra Bahdur, writing in The National in March, called it "rambunctious and innovative". Which, perhaps, is what you might expect from a novelist who has already won the Booker twice - for Oscar and Lucinda in 1988 and True History of the Kelly Gang in 2001. Perhaps, too, there's something globally significant about Carey: an Australian living in America who writes in a distinctively European style.
But a record-breaking third win would be controversial. After all, Carey doesn't need the oxygen of publicity that the Booker provides - whereas Howard Jacobson is probably the most deserving of victory on this list. Often referred to as the "British Philip Roth", Jacobson has suffered the indignity of falling off at the longlist stage on two previous occasions. And while it's actually rather rare for a comic novel to be shortlisted, The Finkler Question explores Jewishness in fine style, without ever belittling the history and culture of his people. His wonderful protagonist, Julian Treslove - who makes a living as a celebrity lookalike - is not Jewish but is intrigued by what Jewishness means. And yet this isn't a book about religion, but humanity.
All of which leaves Emma Donoghue's Room. If there's one book that would most likely go on to sell hundreds of thousands of copies if it wins - and possibly even if it doesn't - it's the seventh novel by this Irish-born, Canada-based author. She's been keen to distance herself from the idea that it's based on the Fritzl case ("It's too strong," she told the Guardian. "I'd say it was triggered by it.") But the links are clear; the five-year-old boy at the heart of this novel, Jack, who is released from a garden shed in the second half of the book, is the same age Felix Fritzl was when his mother emerged from her dungeon. And though it's a tough read, Donoghue uses this opportunity to describe the world with fresh eyes in quite remarkable style.
So who will be celebrating when the winner is announced on October 12? Currently, McCarthy is the favourite - and it's true that for pure virtuosic writing he will be tough to beat. At the shortlist ceremony, though, Motion likened Carey to Charles Dickens, and it's genuinely reckoned (by the author as much as the critics) that Parrot And Olivier in America is his best book to date. It's an incredibly close race, then, but the clever choice would be Donoghue. Somehow, Room seems to have a little bit of everything of the other shortlisted books: the innovation (it's narrated by the child), the strangeness, the delight in language, and the inspiration from a real-life event - all tied up in a compulsively readable and original novel. I hope it wins.