The Puerto Rican screenwriter José Rivera put it best when he recently announced, exasperated: "You can't film the language - and so much of this is a language book." Rivera, whose previous work has included the Oscar-nominated adaptation of Che Guevara's The Motorcycle Diaries, was referring to his current movie project, a big-screen version of beat classic On the Road. Jack Kerouac's famous novel has been in the hands of Francis Ford Coppola since 1979 (when he bought the movie rights) and though it has received plenty of attention from various would-be adaptors, it has generally been regarded, until now, as impossible to shoot in a movie format. Rivera, however, and the Motorcycle Diaries' director Walter Salles, are facing Kerouac's meandering prose head-on, transforming it into workable production pages (the film is scheduled for a 2009 release). If successful the team may be able to finally prove that no book is unfilmable. There used to be a rule about adaptations, of course, which was best summed up by Norman Mailer when he said: "There is a particular type of really bad novel that makes for a really great motion picture." He was referring, possibly, to books such as Gone With the Wind or The Godfather. But in recent years, plagued by a dearth of original content, filmmakers are increasingly ignoring Mailer's law and plundering highbrow literary fiction for as source material. Last year's Oscar headliners were a telling bunch. Ian McEwan's Atonement, Cormac McCarthy's No Country for Old Men and Upton Sinclair's Oil! (filmed as There Will Be Blood) were hardly trashy airport novels. No Country for Old Men in particular is filled with densely elegiac ruminations on the end of the old west which in the wrong hands might have seemed leaden or spurious. (Indeed the writer-directors the Coen brothers ditched huge chunks of the novel's interior monologues for, one suspects, this very reason). However their faithful reproduction of another incident - the death of central protagonist Llewelyn Moss (Josh Brolin), which occurred outside of the action in the novel and was duly translated to screen as an off-camera incident - angered some fans. It raised troubling questions to some about the gap between the two art forms, and the pitfalls of the very adaptation process itself. The protest seemed to be about a perversion of some basic tenets of movie storytelling - tenets that fancy-pants literary fiction has no interest in upholding. And yet it seems, from a cursory look at some upcoming "prestige productions", the trend will get worse before it gets better. Yann Martel's dense, internalised fable, Life of Pi, is rumoured already to be in preproduction with film-makers as diverse as Alfonso Cuarón (Children of Men) and M Night Shyamalan (The Happening) jostling for a place in the director's chair. It seems that what was so formidable and engrossing about that particular book - a close and claustrophobic encounter with a Bengal tiger on a life raft - will inevitably end up as anthropomorphic, computer-generated kitsch, Chronicles of Narnia-style (see Liam Neeson's talking lion, Aslan). Meanwhile, one of the great Hollywood production headaches of 2008, Spike Jonze's adaptation of Maurice Sendak's deceptively simple children's book Where The Wild Things Are, has been forced into reshoots and digital reworking. Studio bosses were allegedly perplexed by how lifeless Jonze's full-sized puppet characters were compared to how lifelike they seemed on the page. Cormac McCarthy's seemingly "unfilmable" 2006 Pulitzer Prize-winning novel The Road is also in production and is presenting all the problems associated with highbrow adaptations. The main hurdles seem to be toning down this bleak, post-apocalyptic novel's gruelling passages for the mass audience. In this case the screenwriter Joe Penhall has increased the number of flashback scenes to the relationship between the bedraggled hero Viggo Mortensen (simply known as The Man) and his wife, played by Charlize Theron. Meanwhile, perhaps the greatest challenge of all will go to the Indian-born Canadian director Deepa Mehta (the Fire, Earth and Water trilogy), who has recently signed up to co-write and direct the adaptation of Salman Rushdie's Midnight's Children. Mehta and Rushdie (who will co-write) are both confident, and have announced a 2010 release date for the movie. But how they will transform the perambulatory adventures of Rushdie's telepathic protagonist, Saleem Sinai, through India, war-ravaged Pakistan, jungle exile and back again, and his deflated, defeated, downbeat ending into digestible screen entertainment is another issue. The novelist Chuck Palahniuk, whose debut novel Fight Club was considered similarly unadaptable, but later became a cult hit starring Brad Pitt and Edward Norton, still admits that the current rush to translate literary fiction into mainstream movies is a concern. "The strength of film is its accessibility and its immediacy," begins Palahniuk, whose fifth novel and New York Times bestseller, Choke, (an unreliable, schizophrenic narrative, including a near-constant internal monologue) has recently been turned into a movie starring Sam Rockwell and Anjelica Huston. "But the strength of books is that freedom to depict anything you want because people are going to be reading them in private. It's just one person agreeing to read a book. "I'm always trying to write with the complete freedom of subject matter that books have. So I'm kind of surprised when my work does get translated into films, because I always think that its subject matter will preclude that." Perceived as unfilmable, Choke is a classic example of the transformation a contemporary hot-button novel will undergo in order to reach the multiplex. Victor Mancini (Rockwell) is a con man who fakes choking incidents in posh restaurants in order to extort compensation from unlucky bystanders. His life revolves around his dementia-afflicted mother (Huston). On the page Palahniuk savagely ruminates themes of human weakness, compulsion and the crushing inevitability of death - the mother is a particularly disturbing creation, a skeleton almost, lying bemused in a care-home bed. In the movie, however, the mother has become vaguely sympathetic, and, as played by Huston, is something of a game old dame, with a twinkle in her eye and a hint of bravado. Her relationship with her son is, thus, far more ambiguous than in it is the original text. Palahniuk, to his credit, says that he was comfortable with these changes. "When I met Sam he said that he really saw the movie as Hamlet, the unresolved mother-son relationship, and that's how he wanted to play it," he says. "I had never made those connections, but that doesn't mean they're not kind of brilliant in their own way. I know that everyone wants to do the best job they can do, so in a way I kind of stay present so that I can validate their interpretation and let them surprise me with where they can take the story. " It might be worth noting that Choke made $2.3 million (Dh8.5m) at the box office in its first two weeks. Despite a small-scale release, it has now grossed a total of $3.1m (Dh11m) worldwide, already recouping its $3m budget. However, the other big-name adaptations mentioned earlier, though mostly in the black, are hardly success stories from Tinseltown's front line. There Will Be Blood had an estimated budget of $30m (Dh110m) and subsequently made, even with the blanket Oscar hoopla, a paltry $40 (Dh147m) at the American box office. Atonement hardly fared better, pulling in $50m (Dh185m) on a purported budget of $30m. Meanwhile last year's star-studded adaptation of Gabriel Garcia Marquez's Love in the Time of Cholera was a whopping dud, taking only $10m (Dh37m) from a worldwide release, on a hefty budget of $45m (Dh165). The cruel reality here, of course, is that something has been lost between page and screen. And it's not some essential spark, or some compelling story arc that might otherwise have turned a flop into a smash. No, the truth is that film-makers have, it seems, become so obsessed with proving that novels can be filmed that they have forgotten to ask whether or not they should. As a closing illustration, in the summer of 1993 I was invited to a special industry screening of a restored print of Mary Ellen Bute's film version of the world's greatest unfilmable novel: Finnegan's Wake by James Joyce. It was a mess, a cacophonous tangle of images and sound that became more and more irksome and tedious as its 92 minutes wore on. At the end, everyone agreed that Bute had done the impossible, and filmed the unfilmable. We also agreed that it was awful and not worth the celluloid it was printed on.