I\u27ve never used the whodunit technique, since it is concerned altogether with mystification, which diffuses and unfocuses suspense. It is possible to build up almost unbearable tension in a play or film in which the audience knows who the murderer is all the time, and from the very start they want to scream out to all the other characters in the plot, Watch out for So-and-So! He\u27s a killer! There you have the real tenseness and an irresistible desire to know what happens, instead of a group of characters deployed in a human chess problem. For that reason I believe in giving the audience all the facts as early as possible. —Alfred Hitchcock ... I. WHY MYSTERIES AND DETECTIVE STORIES? In training sessions for federal habeas corpus att...