The classic Disney film is based on the 1949 children's book, Lottie and Lisa, by German author Erich Kästner. The plot is very similar to both the 1961 and 1998 films, except for the settings; one of the twins lives in Munich, while the other lives in Vienna.
The 1987 movie is based on a 1973 novel by William Goldman — who also happens to be the Academy Award-wining screenwriter.
The movie is based on The Accidental Billionaires: The Founding of Facebook, A Tale of Sex, Money, Genius, and Betrayal by Ben Mezrich, who based the book on conversations he had with Eduardo Saverin, who helped co-found the company.
4. Fast Times At Ridgemont High
Cameron Crowe, who went undercover at a real high school to write the book, also wrote the screenplay for it.
5. Scarface
The book's author, Armitage Trail, moved to Chicago for two years to write the book and based it on the life of Al Capone.
6. Die Hard
Die Hard is based on the 1979 novel Nothing Lasts Forever by Roderick Thorp. The book was actually a sequel to his 1966 book, The Detective, which was made into a movie of the same name in 1968 and starred Frank Sinatra.
7. Who Framed Roger Rabbit
The groundbreaking movie was a based on the 1981 novel, Who Censored Roger Rabbit? Unlike the movie, the toons in the book weren't classic cartoon characters, but were actually comic book characters.
8. Psycho
The book's author, Robert Blach, partially based the character of Norman Bates on real-life serial killer Ed Gein.
9. Planet of the Apes
The movie was based on the 1963 novel by French author Pierre Boulle. Unlike the movie, the book does not take place on Earth, but rather on a far-away planet — it does however offer an equally as surprising twist ending.
11. Homeward Bound: The Incredible Journey
The movie is based on the 1961 children's book The Incredible Journey by Shelia Burnford. She was inspired to write the book because of the love and devotion her children showed to their three pets.
12. Pitch Perfect
The movie is based on the book Pitch Perfect: The Quest for Collegiate a Cappella Glory by Mickey Rapkin. The book was a non-fiction account of the hard work and rivalries between competitive collegiate a cappella.