For as long as the movie industry has existed as a popular art form, books in all their forms have been the subject of cinematic adaptation.

Whether it’s an old or modern classic or a schlocky best-seller, literature has been the source of some of the most loved films in history.

In spite of cinema’s basic, inherent function to take words from the page and visualise them there are certain books, some have argued, that are simply impossible to film and as such will never be seen on the silver screen.

Never say never, though, especially in the movie industry, as time and again the critics are confounded and what was once written-off as ‘unfilmable’ ends up going before the cameras – all be it to varying levels of success.

This has never been more true than today, with several adaptations of books that have previously been deemed too complex or challenging to work as films reaching our cinemas. Just recently, we’ve seen an admirable take on Jack Kerouac’s defining beat generation work On The Road by Walter Salles, Ang Lee’s version of Yann Martel’s beloved novel Life of Pi and a bold adaptation of David Mitchell’s sprawling epic Cloud Atlas by the Wachowski brothers and Tom Tykwer, while this month also sees the cinematic release of Salman Rushdie’s critically lauded book Midnight’s Children.

This is hardly a new phenomenon, however. Stanley Kubrick’s adaptation of Vladimir Nabokov’s controversial tome Lolita arrived in 1962 (the film poster even states “How did they ever make a movie of Lolita?”). Mike Nicholls faced major challenges bringing Joseph Heller’s satirical anti-war classic Catch-22 to the big screen in 1970, while more recently Peter Jackson finally delivered a truncated, but no less epic production of J.R.R Tolkien’s The Lord of the Rings to huge acclaim.

Some directors have taken a more metatextual approach, including David Cronenberg who brilliantly weaved events from William Burroughs’ life into a unique adaptation of the writer’s drug-addled opus Naked Lunch. Michael Winterbottom’s A Cock and Bull Story inventively (and hilariously) acknowledged the difficulty of realising Laurence Sterne’s 18th century novel Tristam Shandy on screen by adopted the film-within-a-film approach, while Charlie Kaufman channeled his head-banging struggle to write a script for The Orchard Thief to ingenious effect in Spike Jonze’s Adaptation.

As Cronenberg, Winterbottom and Kaufman/Jonze have proved, the book is merely the beginning of the process, it needn’t have to be the end. For years movies have been ‘printing the legend’ and playing fast and loose with ‘true’ stories, so why shouldn’t the adaptation of novels be any different?

As Lee has stated on adapting Life of Pi: “We can never write a book or make a movie as good as how it plays in the audience’s mind.”

Once published, a book no longer belongs to the writer, it becomes the intellectual property of each and everyone who visualises the words they are reading in their own heads. A film is just another visualisation of the material, it just happens to be the one that gets the most attention.

When the source is a graphic novel, problems can occur as the author/illustrator have already set down how it should look. Zack Snyder was on a hiding to nothing when he adapted Alan Moore’s seminal Watchmen, thought to be one of the medium’s most unfilmable works.

Snyder tried to stay as close to Moore’s vision as he could, but compromises inevitably needed to be made, incurring the ire of both the author and some within the fan community.

Directors and screenwriters will invariably tell you it’s not their job to come up with an ultra-faithful translation of the source. An adaptation is exactly that, an interpretation of the material that should be taken on its own merits.

So-called ‘unfilmable’ books should be treated no differently; we can only hope screenwriters and directors continue to have the vision necessary to bring these texts to the big screen. After all, the books aren’t going anywhere.