Next week sees the release of Cloud Atlas, the movie version of one of the most famously unfilmable books of all time. But Cloud Atlas isn't the first supposedly unfilmable book to make it to the screen. There have been several classic novels that everybody thought couldn't be captured on film — until somebody did it. With mixed results.


Here are 11 unfilmable books that have been filmed... including two that are coming next year.

What makes a book unfilmable? We ponder the question at greater length here, but it seems like usually it's about a couple things: 1) Complexity and length. 2) Visuals. 3) Challenging ideas. The challenge of creating huge visuals is becoming less of a problem as CG effects get more successful and versatile, but the other two problems might actually become more acute as movies become more expensive and thus need to appeal to the biggest possible audiences.


Dune

Why it was unfilmable: Mostly complexity, but also challenging ideas. The AV Club argues that Dune really is unfilmable: "Dune is simply one of those books packed with far too much abstract philosophy and internal action and dialogue, which can't be excised from the story or portrayed effectively in a visual medium." Adds John Scalzi: "Frank Herbert's book jammed together religion, politics, ecology, revolution and big honkin' spice-excreting annelids into a text so dense it threatens to implode into itself."

How they filmed it: David Lynch condensed the story considerably, but as Scalzi puts it, he also "added his own layer of weirdness to it." The Sci Fi Channel did a more straight-up adaptation in a miniseries, with mixed results.


Watchmen

Why it was unfilmable: Mostly length and complexity — there are a ton of characters and insane amounts of backstory, and Alan Moore and Dave Gibbons' seminal work relies on the comics format to pack in a ton of drama. And it's a huge 12-issue miniseries. But also challenging ideas: the story takes place in an alternate history where Richard Nixon is president for life, and superheroes are part of our political fabric. As director Terry Gilliam said in 2000, "The problem with Watchmen is that it requires about five hours to tell the story properly, and by reducing it to a two or two-and-a-half hour film, it seemed to me to take away the essence of what Watchmen is about."

How they filmed it: Director Zack Snyder made a fairly lengthy movie, in which a lot of backstory is packed into a beautiful opening title sequence, and some subplots are drastically curtailed. As Watchmen goes on, it turns into more of a traditional action movie, until it ends with a Matrix-esque fight scene among the heroes while people talk about tachyons. I'm not sure what someone who hadn't already read the source material would make of Snyder's film.


V for Vendetta

Why it was unfilmable: Another Alan Moore graphic novel, another huge miniseries with a ton of digressions, and another tough political subtext. Alan Moore categorically seems to believe that all of his works are unsuitable to be turned into films, but V for Vendetta is another one that Moore seems to believe couldn't be filmed. The comic depicts a post-apocalyptic Britain descending into fascism under the leadership of a man who's in love with a computer, while a mysterious terrorist in a Guy Fawkes mask fights back against the state and tortures a young girl to try and turn her into his successor.

How they filmed it: The movie version features a more upbeat ending, and less of a focus on pure anarchism, among other things.


The Neverending Story

Why it was unfilmable: Michael Ende's actual novel is a complicated meditation on how stories change us and how we change them — in the first half, young Bastian reads a book about a hero named Atreyu, only to find the story changing in response to his reactions. In the second half, Bastian actually goes inside the story and explores the fantasy world himself. It's full of weird ideas, like Bastian gets a medallion that grants wishes — but every wish makes Bastian lose another piece of himself.

How they filmed it: Michael Ende was so upset with the 1984 film version, he famously sued to have the title changed or his name taken off it. The movie only covers the first half of the book, and leaves out a lot of the ideas that Ende explores.


A Scanner Darkly

Why it was unfilmable: This Philip K. Dick novel is one of his weirder stories — and the notion of an undercover cop who's forgotten that he's the guy he's investigating is really kind of jarring and something that would be difficult to convey on the screen. The novel plays a lot with the notion of reality and identity being consensual illusions, covering up a reality that's both darker and impossible to know. And so on. This novel was included, along with Watchmen, in a recent class on unfilmable books that were adapted to film anyway.

How they filmed it: Richard Linklater uses rotoscoping to turn Robert Downey Jr. and Keanu Reeves into trippier, more cartoony versions of themselves, and creates a kind of "slacker" version of Dick's narrative. And, as Tasha Robinson explains in the AV Club, the result is "an astonishingly accurate adaptation, though it streamlines the book to the point where the story is much easier to follow if you have the book in mind and can fill in the gaps yourself."


The Host

Why it was unfilmable: This novel by Stephenie (Twilight) Meyer is a bit challenging because it takes place in a world that's been conquered by aliens. But mostly, it's because a lot of the action involves Melanie arguing with the alien parasite inside her head. She's literally having long conversations with a voice in her head, and it's hard to see how this can be made dynamic on screen, even with the great Saoirse Ronan playing Melanie and her alien parasite. And they're both in love with the same guy.

How they filmed it: The footage we saw at San Diego Comic Con featured Saoirse Ronan getting yelled at by a voice in her head, and it was kind of weird to watch. To be fair, this probably isn't unfilmable, just hard to translate to screen in a non-clunky way. Maybe over the course of a full-length movie, it'll seem normal. We'll find out in March!


The Lathe of Heaven

Why it was unfilmable: Complexity as well as weird ideas. Ursula K. Le Guin's novel about a man whose dreams reshape reality is a challenging, weird story that deals with some of the same questions as Dick's novel, about reality and identity. It's steeped in complicated philosophical notions and features a lot of weird trippy stuff, as the fabric of reality gets more and more warped by George's weird dreams.

How they filmed it: PBS made a TV movie version in 1980 that was shockingly faithful to the novel, and remains the only adaptation of her works that Le Guin endorses. The special effects are bargain basement, but the ideas are intact and the overall effect is actually super chilling and intense. There was a 2002 remake that basically tosses a lot of Le Guin's story out the window.


Lord of the Rings

Why it was unfilmable: Length, complexity, and completely insane visuals. J.R.R. Tolkien's masterpiece is a huge sweeping story with massive set pieces and tons of characters — this is the greatest fantasy epic of all time, and the "epic" part is really serious.

How they filmed it: Peter Jackson's three films do a pretty incredible job of bringing a lot of the visuals to life, thanks to some huge advances in computer effects as well as some insane dedication on the part of workers at Weta Workshop (who created so much chain mail armor they rubbed the fingerprints off their thumbs and forefingers.) At the same time, Jackson takes some liberties with Tolkien's story, and also reserves huge chunks of the story for the extended DVD cuts of the films.


Johnny Mnemonic

Why it was unfilmable: Complexity and ideas, basically. This William Gibson short story is unfilmable in the sense that a lot of Gibson's ideas are hard to capture on the big screen — it's very cerebral, and there's a lot of stuff happening at once. A lot of the ideas are very hard to visualize, in general.

How they filmed it: In a nutshell, the film version is widely regarded as a mess, which substitutes over-the-top performances from its supporting cast for any real exploration of Gibson's ideas. It has a 14 percent fresh rating on Rotten Tomatoes.


Ender's Game

Why it was unfilmable: This Orson Scott Card novel has often appeared at the top of people's lists of unfilmable novels, for a few reasons. It's a particularly brutal, cynical story about a boy who's coopted by the military establishment in a dystopian future, when the world is at war with "Formic" aliens. And there are several other challenges. As Pajiba says, "I don't just mean that CGI can't make twenty pre-teens competent enough actors that we become convinced they are geniuses. I mean that the action of the novel all happens in Ender's head. The empathy, the struggle, the quiet watching and learning. That invisible internal struggle cannot be directly filmed, and I don't see this story retaining its greatness without it.

How they filmed it: They've already filmed this story, but we won't get to see the result until November 2013 — thus far, it's obvious that a ton of attention to detail went into every aspect of the sets, and the cast includes Harrison Ford and Ben Kingsley. So fingers crossed!