Stanley Kubrick considered "The Killing" (1956) to be his first mature feature, after a couple of short warm-ups. He was 28 when it was released, having already been an obsessed chess player, a photographer for Look magazine and a director of "March of Time" newsreels. It's tempting to search here for themes and a style he would return to in his later masterpieces, but few directors seemed so determined to make every one of his films an individual, free-standing work. Seeing it without his credit, would you guess it was by Kubrick? Would you connect "Dr. Strangelove" with "Barry Lyndon?"