Joseph Stefano

Hitchcock took one look at Robert Bloch's 1959 novel Psycho and screamed in panic and/or joy. This full of blood and gore and sex, he said to himself. That's the movie for me!

Hitchcock initially asked screenwriter James P. Cavanagh to do a screenplay—but the director didn't like the results (not enough blood, gore, or sex). So he turned to Joseph Stefano, a relative newcomer, who had written Martin Ritt's The Black Orchid in 1958.

Stefano's script was daring. It was his idea to start the movie with Marion, so that she became the main character before getting killed off. "The idea excited Hitch," Stefano said. "And I got the job. Killing the leading lady in the first twenty minutes had never been done before!" (Actually, Marion survives to about the fifty-minute mark—but you get the idea.) (Source)

Stefano also changed the character of Norman substantially. In the book, he's older, overweight, and generally more unpleasant in appearance—harder to sympathize with, in other words. Stefano made Norman younger, nervous, and innocent. That way he keeps the audience's sympathy… even after Marion is killed.

Hitchcock wanted Stefano to work on The Birds and Marnie, but the writer was tied up writing for the television anthology series The Outer Limits. After that… well, Stefano didn't get many other big jobs of note. He did some TV movies, some features, and some bits and pieces.

You'd think after writing one of the most innovative and famous scripts in the history of cinema, you'd be in demand. Instead, his moment in the limelight ended abruptly. Kind of like Marion Crane's… but with a lot less blood and drama.