Inspiration for movies comes from many places: plays, songs, true stories—even the occasional app can inspire a screenwriter and motivate a studio. But books remain the most frequently visited well for cinematic inspiration. Of the hundreds of movies based on books, here are the ten best.

The Shawshank Redemption (1994)

Based on: A 1992 novella by Stephen King entitled “Rita Hayworth and the Shawshank Redemption.”

Back cover blurb: Andy Dufresne (Tim Robbins) is convicted of the murder of his wife and her lover. He claims he is innocent. The film follows Andy as he tries to survive cruel Shawshank State Penitentiary. He’s helped and counselled by fellow prisoner, Red, played by Morgan Freeman in an Oscar-nominated performance.

Key difference: Red is an white Irish man in the book, while in the film Freeman’s character jokes that he is Irish.

This will be on the test: The King novella also included the source material for the films Apt Pupil and Stand By Me.

Harry Potter and the Prisoner of Azkaban (2004)

Based on: The book of the same name by J.K. Rowling, the third in her wildly popular Harry Potter series.

Back cover blurb: Harry Potter (Daniel Radcliffe) spends his third year at Hogwarts School of Witchcraft and Wizardry tracking the mysterious story of Sirius Black (Gary Oldman), an ally of He Who Must Not Be Named and a prisoner in Azkaban.

Key difference: The Marauders and their map play a huge role in both the book and the movie, but their backstory and the ways that the map is used differ slightly on-screen.

This will be on the test: After Richard Harris, who played Dumbledore in the first two Harry Potter films, passed away, Ian McKellen was offered the role, but turned it down.

Gone Girl (2014)

Based on: The 2012 beach read classic by Gillian Flynn.

Back cover blurb: Amy Dunne (Rosamund Pike), who has a seemingly perfect suburban life and the seemingly perfect childhood—as illustrated in a successful line of books written by her parents—suddenly disappears and all eyes are on her shady husband Nick (Ben Affleck).

Key difference: Though they still author the Amazing Amy books in the film, Amy’s parents play a much smaller role in David Fincher’s film. Nick’s dad, who also plays a big role in the book, is barely seen on-screen.

This will be on the test: Reese Witherspoon produced the film and intended to play Amy, but withdrew from casting contention after chatting with director David Fincher about his vision for the role.

The Color Purple (1985)

Based on: Alice Walker’s searing and seminal 1983 novel.

Back cover blurb: Celie (Whoopi Goldberg) writes letters detailing her often painful life in rural Georgia, her separation from her sister, Nettie (Akosua Busia), her relationships with her husband’s son’s wife, Sofia (Oprah Winfrey), and her husband’s sometimes-mistress, Shug (Margaret Avery).

Key difference: The book delves even deeper into the inner lives of the women in Celie’s life and paints a more complex picture of the relationships they share.

This will be on the test: This was Whoopi Goldberg’s first film and she received her first Oscar nomination for it.

Atonement (2007)

Based on: Ian McEwan’s 2001 metafictional novel.

Back cover blurb: Precocious and imaginative Briony (Saoirse Ronan) stumbles upon her sister (Keira Knightley) and her boyfriend (James McAvoy) in an intimate moment. Briony misinterprets what’s happening, setting in motion a tragic chain of events that affects them all for years.

Key difference: McEwan’s book is deliciously cerebral and interior, giving the characters’ conflicts, questions, and changes vigorous life. Joe Wright’s film must externalize these inner workings and uses a spare, lush cinematic language to do so.

This will be on the test: The book Atonement is based on another book, Henry James’ What Maisie Knew.

The Wizard of Oz (1939)

Based on: L. Frank Baum’s 1900 book The Wonderful Wizard of Oz.

Back cover blurb: Kansas farmgirl Dorothy (Judy Garland) is transported by tornado to a magical land where she immediately murders someone and steals her shoes. She then forms a gang and sets off to storm a city with a list of demands for the local wizard.

Key difference: Dorothy’s iconic ruby red slippers were silver in the book.

This will be on the test: The horses in Emerald City were colored with Jell-O crystals.