Sometimes there just isn't much to say about a book/movie comparison. So here's an abbreviated seek the original of:
(Book by Robert Bloch. Movie: 1960 by Alfred Hitchcock)
I enjoyed the book and the movie, but still have very little to say about them. It's impossible to discuss this in any detail without spoilers.
Bloch's book is written in a loose, informal, internal monologue style. It's a tale of the ultimate mamma's boy. A man named Norman Bates living alone in a house running a small hotel is actually more a boy than a man. He's still living with the scars of his overbearing mother. He still protects her, cares for her, loves and fears her. So when a beautiful young woman comes to the hotel, and Norman has a slight inclination of being an adult man, mother steps in to protect him from temptation by killing the woman while she showers. It of course doesn't end there. People come looking for her, and now Norman has to cover it up. He has to protect his mother.
Hitchcock's movie follows the book's story fairly close, which surprised me. The book puts us in very intimate touch with Norman's thoughts, and because much of the book takes place from his point of view, his thoughts on mother make her real. The mother presence in the movie isn't nearly as real as it should be.
Much of the internal monologue is replaced by dialogue, but Norman doesn't sound or act like a man suffering from the scars of an abusive mother and decades of isolation. He's not that creepy at all in the film. There was plenty of dialogue in the book that established what he is, but none of it was used. The book of course allows us to get to know him a lot better, and it makes all the difference because we see a lot more of the disturbed mamma's boy. The film barely shows it.
The movie tells the story well enough, but the book is still much better.