Is the "One Flew over the Cuckoo's Nest" movie extremely similiar to the book or different?

Answer 1

They actually did a pretty good job of making the movie and keeping the essentials of the book. Of course, no movie is going to be able to convey all the texture of any book.
But this one, with a great cast: Jack Nicholson as Randle Patrick McMurphy, Louise Fletcher as Nurse Mildred Ratched, William Redfield asHarding, Michael Berryman as Ellis, Danny DeVito as Martini, Christopher Lloyd asTaber and Will Sampso as Chief Bromden (Big Chief.) comes closer than any other attempt I've ever seen

It won the 'top five' Oscars (for Best Picture, Best Actor, Best Actress, Best Director and (here's the important one for its being faithful to the book) Best Screenplay.

It's one heck of a movie made from a great novel.