Today is the 100th anniversary of the birth of Alfred Hitchcock. Already a successful British director, Hitchcock went to Hollywood just before World War Two. Over the next four decades he became internationally famous through his films and TV programs. He was a shy man who loved publicity. He called actors "cattle," yet sometimes got performances out of them that no-one else could. He said that movies were just sequences of images, yet he became one of Hollywood's most beloved storytellers. David D'Arcy looks at Hitchcock's career.