It's no secret that Hollywood looks all over the place for inspiration, and one of their main sources for ideas is the world of literature. Books already have characters with great story arcs and, usually, interesting problems that they need to overcome — and, if the studio is really lucky, a large and devoted fan following.

There have been plenty of mainstream book to film adaptations that have gone on to be huge hits. Everyone knows that the Harry Potter and Twilight franchises were spawned from their respective books series. The Hunger Games and The Fault In Our Stars were big successes as well, both on and off the screen. While Hollywood looks to the library shelves in search of the next big thing, we thought we'd take a look back at films that many people wouldn't necessarily associate as adaptations.

Here are Screen Rant's 13 Movies You Didn't Know Were Based On Books.

13. Mrs. Doubtfire (1993)

Although it would seem that this particular film was written specifically for Robin Williams, given his amazing portrayal of the titular character, it is actually not the case. The film is, in fact, based on the 1987 novel Alias Mrs. Doubtfire by Anne Fine, in which a father dresses up as an elderly British woman and gets hired as a nanny, in order to spend more time with his kids.

This film is a faithful adaptation of the original novel, right down to the names of the characters being the same in both cases. The story arc and major plot points all remain the same, the true essence of the story, which comes across in a big way on the big screen. What set the movie apart are the performances, which are pretty spectacular. Mrs. Doubtfire shows off the late Robin Williams’ comedic timing to perfection, but it’s the heart that really shines through, making the film one of the best and most faithful book to movie adaptations around.

12. Drive (2011)

It’s interesting to realize that we never would have gotten one of Ryan Gosling’s best performances to date, had it not been for a book to film adaptation. The story of an unnamed Hollywood stunt man, turned getaway driver, whose life goes to hell after a bad job, is actually based on the 2005 novel Drive, by James Sallis.

Plot-wise, the film is a pretty faithful adaptation of the novel, which is impressive, given that the novel is only 157 pages long. While it’s still a crime drama with a revenge tale woven throughout the narrative, the main differences come in the form of the characters themselves. In the novel, while Driver is guarded, he manages to have friends and develop relationships with other people. In the film, Gosling plays the character so closed off, it’s hard to get a word out of him, or a read on him. The film also took liberties with some of the other characters, including making Irene a blonde, blue eyed love interest for Gosling’s character. The film is an adaptation of what Nicholas Winding Refn saw between the lines in the novel, but it’s done so masterfully that you can’t fault the director for taking some liberties.

11. The Princess Bride (1987)

The ultimate romantic/fantasy/adventure/comedy film of the 1980s got its start on the page, in the form of the 1973 novel The Princess Bride by William Goldman. The novel is portrayed as an abridgment of S. Morgenstern’s Classic Tale of True Love and High Adventure, with Goldman’s commentary peppered throughout, but it is, in fact entirely Goldman’s work. The ‘autobiographical’ parts in the book are fictitious.

The film follows the novel closely, which isn’t surprising given that Goldman, an award-winning screenwriter, also wrote the script. The film is witty and romantic, (as well as extremely quotable) with characters you can’t help but fall in love with. The adventures of Westley and Buttercup and all of their friends, are brought to life with such splendor, it’s hard to find any fault with this adaptation. From the book to the script, through the casting and then finally, the direction, this film is the quintessential fairy tale.

10. Jaws (1975)

Yes, the film that ushered in the summer blockbuster and everything that comes along with it, was actually based on a novel. Steven Spielberg’s first hit has its roots planted in the 1974 novel, Jaws, by Peter Benchley. The story of a massive great white shark attacking and eating people on vacation was a huge hit on both the page and the big screen.

This one is less than a direct adaptation and more of a based on type of scenario. A number of changes were made to the source material during production, including the removal of a subplot that had Ellen Brody having an affair with Matt Hooper and a change in location from Long Island to Massachusetts. Spielberg also found Benchley’s characters rather unlikeable, so they were rewritten to be a bit more relatable to mainstream audiences. Basically, the first two-thirds of the film is original material, with the final third being truest to the source material. Even with the changes, the film is a masterpiece and deserves the title of one of the greatest films ever made. It’s suspenseful and frightening and its appeal can’t be denied.

9. Forrest Gump (1994)

The role that won Tom Hanks his second of back to back Oscars wouldn’t have been possible had it not been for the original novel. The Oscar winning picture is based on the 1986 novel, Forrest Gump, written by Winston Groom. The story follows the life of Forrest Gump, as slow-witted, but good hearted man as he witnesses and sometimes influences, some of the biggest moments in the latter half of the 20th century.

The film takes quite a few liberties with the source material, basically switching the main focus of the story to the love story between Forrest and Jenny, while making Forrest’s grand adventures a secondary story arc. The film is a beautiful tale that takes a look at the world through the eyes of a gentle soul and Zemeckis captures the spirit of the novel, bringing the characters and story to life in such a way as to make them memorable, long after the credits role.

8. Mean Girls (2004)

You would think that a satirical and hilarious look at teen culture through the eyes of a girl who has never been exposed to the world of high school before, would be a fun read. At least until you realize that the Tina Fey comedy was actually based on a non-fiction self-help book entitled Queen Bees & Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends & Other Realities Of Adolescence by Rosalind Wiseman.

Given the source material, it’s not surprising to learn that Tina Fey wrote the script from scratch, using the book and her own high school experience as a guide. With its memorable characters, and whip smart dialogue, the film showcases not only the best of star Lindsey Lohan, but also the fantastic wit of Fey. While it’s not the only film to be created from a self-help book, with titles like He’s Just Not That Into You and What To Expect When You’re Expecting as competition, it’s easy to see why this is considered the best one of the bunch.

7. The Town (2010)

Ben Affleck’s second directorial effort after the incredible Gone, Baby, Gone started life as Chuck Hogan’s 2004 book, Prince Of Thieves. The story follows a group of thieves from the Boston neighborhood of Charlestown, as they work their way through a number of heists.

The film sticks closely to the original material, only deviating slightly to bring a little more action to the screen (in the form of an armoured car chase) and to play up the relationship between Doug and Claire, which is actually more of a love triangle with Agent Frawley in the novel. The choice to bring the Doug and Jem relationship to the forefront and make it the centerpiece of the film was the biggest and probably the most brilliant alteration from the novel. Jeremy Renner’s portrayal of the slightly unhinged Jem is a work of art, and unsurprisingly, earned Renner an Oscar nod. The artistic liberties made to the source material do nothing but enhance Hogan’s exceptional story and make this film a definite must see.

6. First Blood (1982)

John Rambo isn’t necessarily a name that you would associate with the written word, but the story of a troubled Vietnam vet who is forced to use his training to survive abusive small town law enforcement officials did in fact start off as a book. The 1972 novel by David Morrell, entitled First Blood, is the basis for the film.

The film, which took more than ten years and approximately eighteen script rewrites to finally get off the ground, does deviate from the source material quite a bit. The character of John Rambo is portrayed much more sympathetically and the ending of the film was altered dramatically (we won’t go into spoilers, in case someone wants to give the novel a read). The film is considered very influential to the action genre, which isn’t surprising given its bloody and violent nature. But there’s more to it than that, as the film also has an interesting subtext in regards to the idea of war itself. That, coupled with a powerful, yet understated performance by Stallone make this film a classic piece of action cinema.

5. Shrek (2001)

The loveable ogre with a penchant for complaining was actually created by author William Stieg in his 1990 picture book entitled Shrek! The original story saw a monstrous and cantankerous ogre on a journey to see the world, who somehow winds up becoming a hero by saving a princess.

The film, one of the first projects green-lit by Dreamworks, is only inspired by the book, as the entire screenplay was written and then rewritten from the ground up on a number of occasions. It’s not surprising, given that it’s sort of difficult to turn a 32 page picture book into a 90 minute movie without having to add a little something else to the mix. The love story between Fiona and Shrek was fleshed out, as were the other storybook characters and locations. Add in the voice talents of Mike Meyers, Cameron Diaz and Eddie Murphy, and you’ve pretty much got movie magic. Shrek is one of those animated films that appeals to both kids and adults alike, mainly because the studio didn’t dumb the story down. The film is smart, funny and highly entertaining, which just goes to show that sometimes even just a small idea can lead to something grand.

4. Psycho (1960)

Alfred Hitchcock’s seminal masterpiece first began life as the 1959 novel, Psycho, written by author Robert Bloch. As everyone knows, it tells the story of motel owner Norman Bates and his interesting, and disturbing, relationship with his mother.

The film is a fairly faithful adaptation of the original novel, although there were some changes made to the character of Norman Bates in the final product. Screenwriter Joseph Stefano found the character in the novel to be unsympathetic, but was intrigued by the choice of Anthony Perkins for the role. Some of Norman’s more unsavory characteristics from the novel were eliminated, like his penchant for the occult and pornography, leaving the character a bit more of a mystery to audiences. The character of Marion was also given a bigger role in the film, with the reasoning behind it being that any sympathy the audience had for her would be transferred to Norman after she was killed, due to the maternal apathy she showed towards him earlier in the film. Perkins’ portrayal of Norman Bates is the stuff of legend, the kind of performance that stays with you. An exceptional entry into the horror genre, the film manages to transcend the slasher film label and is a stunning work of filmmaking, period.

3. Requiem For a Dream (2000)

Darren Aronofsky’s stunning look at drug addiction wouldn’t have been possible if not for the 1978 novel by Hubert Selby Jr. Requiem For A Dream follows the downward spiral of four people who are afflicted with various forms of drug addiction.

The Oscar nominated film is a fair adaptation of the source material, which isn’t surprising since Aronofsky wrote the screenplay with Selby at his side. The film has a little more artistic flair than the brutally written and stark words of the novel, but neither sugar coat the character arcs or consequences of each of the characters' choices. Instead, we get a stark portrayal of the delusions and desperation that come with addiction. The psychological drama is considered one of Aronofsky’s best, and for good reason. Gena Rowlands was nominated for an Oscar for her breathtaking performance, though she wasn't the only standout in a film full of amazing performances. The film is a definite must see for film lovers.

2. Who Framed Roger Rabbit (1988)

The live-action/animated hybrid first came to life on the page in the 1981 mystery novel Who Censored Roger Rabbit? by Gary K. Wolf, in which second string comic strip character Roger Rabbit hires private investigator Eddie Valiant to discover why his employers have reneged on giving him his own strip.

While the characters in both the novel and the film have the same names, their characteristics and the overall plot of the story are very different. In the novel, which takes place in present day (or, present day 1981, as it were) the cartoon characters are actually comic strip characters that speak with word balloons over their heads. And Roger gets killed early on, which makes the title of the novel a little more understandable. It’s completely reasonable to see why Disney decided to change all of that and make the film, the first of its kind, a little more family friendly. Overall, the original source material is darker and more adult-oriented than the film, but that doesn’t stop the movie from being exceptional in all the ways that count. A marvel and a must see for people of all ages, the film shows that animation and live action can live harmoniously together when done correctly — and with heart.

1. Die Hard (1988)

Yep, that’s right. The quintessential '80s action flick that launched Bruce Willis into A-List territory has its roots in literature. The film is based on the 1979 novel Nothing Lasts Forever by Roderick Thorp, which is actually a sequel to his novel The Detective. (The first novel was made into a film in 1968, which starred Frank Sinatra).

The studio was contractually obligated to offer Sinatra the part in the film, but when he passed, they developed the property into a standalone project. Other than changes to remove any references to The Detective, the film follows the source material closely. In fact, some of the characters, scenes and dialogue in the film are taken directly from the novel.

The main differences — like McClane’s age (he is younger in the film than in the novel) and the reasons for the hostage situation — were made to not only update the setting to modern day but to distance the film from its predecessor. The film turned Willis into a bonafide action star, and started the whole 'lone hero takes on all the bad guys' craze that came after. His performance is one for the ages, and to see him pitted against Alan Rickman’s Hans Gruber is just the icing on the cake. Considered a classic, Die Hard is the story of an underdog who takes on the bad guys and wins. But who really wins in the audience, as this film is one of the best book-to-film adaptations out there, whether or not the fans know where McClane originated from.

Which of our selections surprised you the most?  What are some of your favorite adaptations? Be sure to let us know in the comments.