With the impending creation of a film version of Ayn Rand’s Atlas Shrugged, the debate about “unfilmable” books rises again. Unfilmability is the reason a certain number of highly regarded and popular books never make it to the big screen—whether because their content is considered too violent to be filmed (as in the case of Bret Easton Ellis’s American Psycho), or because the literary voice can’t be translated to a visual medium (as with Kurt Vonnegut’s Cat’s Cradle). But some filmmakers see these difficult cases as a challenge to put paper to celluloid.

Even the late great Stanley Kubrick considered a film version of Patrick Süskind’s Perfume (newly released under director Tom Tykwer) an impossible project. And this is the guy who took on Clockwork Orange. Strictly as a film, Perfume has received critical acclaim, but reviewers still complain that the movie falls short of the book in terms of capturing the world of scent: instead of evoking odors through description, it “tried to convey smell through close-up shots of the protagonist's nose—of which there were no less than 27.”

Rand fans are afraid a similar fate will befall their beloved Atlas Shrugged, a thinly veiled manifesto for her political ideology. In fact, despite the increased readership and hefty rights payments to the author a film version can bring, many fans hold that certain books were meant to remain untouched.

Take, for instance, the perennial favorite Catcher in the Rye. Filmmakers have been trying to get their hands on this bestseller for years to no avail. Salinger himself stands in their way, refusing to sell the rights. A Hollywood version of a literary classic often brings along plot changes, simplification, screenwriters’ poetic licenses, and dilution of the stuff that made the work great. It’s like trying to watch Michael Jordan play baseball: it’s just not what he does best.

There is room for hopeful or adventurous directors in the realm of the unfilmable, though. Consider Michael Winterbottom, who directed the film Tristram Shandy: A Cock and Bull Story, which is a film within a film about a book. The film tracks the efforts of actors and directors to shoot a film called (what else?) Tristram Shandy, a novel long considered unfilmable because of the ridiculous number of tangents the narrator himself takes. However, the film ingeniously captures the sentiments of the novel as scenes are shot, discarded, shot again, and discarded again, as production crews get distracted by their own lives. Eventually the filmmakers decide that the film is too difficult to shoot, and scrap the entire project. Winterbottom understood the inherent problems in developing a difficult book, and chose instead to take a new tack, perfectly capturing the true sentiment of the novel without mucking up the storyline. It’s a creative approach that works for those who’ve read the book, and those who haven’t.

TIP: If you’re an author and you don’t pride yourself on your unfilmability, check out these suggestions by leading screenplay writer Michael Hauge for developing and pitching your story to studio bigwigs.