I read an intestng book lately. It's The 50 Greatest Movies Never Made", by Chris Gore.
Author Chris Gore has found some fascinating examples of movies that never made it to the screen. However, I find it hard to believe that David O. Selznick saved the rights to the words "Mein Kampf" in case he decided to make a movie based on Hitler's book.
Aparrently, Selznick went so far as to consider using Ben Hecht and Alfred Hitchcock to make the film. Wow.