Jack Nicholson was offered the role of Paul Sheldon but passed because he wasn't sure he wanted to do another movie based on one of Stephen King's novels after what he had experienced with Stanley Kubrick on The Shining.
Anjelica Huston was offered the leading role, and was interested, but was unable to accept it due to her commitment to The Grifters. Bette Midler also turned the role down before it went to Kathy Bates.
In a recent interview with Melvyn Bragg, William Goldman revealed that few actors wanted the role of Paul Sheldon because Annie Wilks overshadowed him so much as a character. Warren Beatty commented before declining that the hobbling scene made Paul Sheldon "a loser for the rest of the film". Goldman was determined to keep that scene in the film as it was his favorite from the Stephen King novel.
Stephen King had originally planned to release the novel under his pseudonym, Richard Bachman. While writing it, however, it was discovered that King was Bachman. King subsequently published the novel under his real name, and announced that Bachman had died from "cancer of the pseudonym."
Stephen King was quite impressed with Kathy Bates's performance in this film, so much so that he later wrote to more roles for her. The title role in his novel Dolores Claiborne was written with Bates in mind. King also wrote the script for The Stand. His original novel featured a (male) character named Ray Flowers. Upon hearing that Bates wanted to be involved in the mini-series, King re-wrote the part as a woman, just so Bates could play the part.
According to the director Rob Reiner, Annie Wilkes' killing spree is loosely based on that of Genene Jones, a nurse who is believed to have killed as many as 50 children who were in her care over a two-year period.
After refusing to speak about his motivations for writing Misery for two decades, Stephen King finally came out and stated that it is indeed about his battle with substance abuse. Kathy Bates' character is a representation of his dependency on drugs and what it did to his body - making him feel alone, separated from everything, while hobbling any attempts he made at escape. In his statement he said he didn't come out with it at the time because he wasn't ready and because he was afraid it would detract from the story.
In the movie, Annie forces Paul to burn his manuscript which is "untitled" (as seen in the closeup). In the novel, Paul titles it "Fast Cars" and is a story reminiscent of 1950s detective dramas and 180 degrees away from the Victorian Era set "Misery" novels that made him famous.
The trivia items below may give away important plot points.
In Stephen King's novel "Misery", Annie cuts off Paul's foot to prevent him from escaping. Screenwriter William Goldman has stated that the reason he decided to adapt the book to film was because of this gruesome scene and the effect it would have on the audience. However, Rob Reiner and Andrew Scheinman's script revision changed the method of torture to Paul getting his ankles broken with a sledgehammer. Goldman was opposed to the change until viewing the film.
Kathy Bates reportedly was disappointed that a scene was cut in which she kills a young police officer by rolling over him repeatedly with a lawnmower. Director Rob Reiner was afraid that the audience would laugh at it.
When Annie demands that Paul burn his manuscript, she lights the paper and we see a close-up of the words on the paper, an article about Cameron Crowe and how he is an amazing scriptwriter. It talks about his movies, but mostly offers praise for Say Anything....
Annie (Kathy Bates) places a wooden block between Paul's (James Caan) ankles and uses a sledgehammer to "hobble" him. In the book written by Stephen King Annie cuts his feet off with an ax. The scene was changed so that there wasn't too much gore.