Warning: wikipedia contains spoilers
The book and film are substantially different. The book is narrated by Marnie herself, a young con-woman with a dark secret in her past. At the end of the story, it is not clear whether she will be able to shake off her psychological problems and embrace normal life.
The film starred Tippi Hedren and Sean Connery. Hedren plays the title character, Marnie, a woman who has an unknown fear and hatred of men. Connery plays Mark Rutland, a man who owns a large business that Marnie gets a job at, in order to steal from it. Rutland finds out that she has stolen and instead of turning her over to the police, he blackmails her into marrying him. He than attempts to discover the reason for Marnie's behavior.
Diane Baker, Martin Gabel, Mariette Hartley and Alan Napier also appeared in the movie.