Code Breaker Leo Marks Code breaker Leo Marks died January 15th at the age of 80. He served as one of Britain's top code makers during WWII. There he revolutionized the military's code making methods. He wrote about his experiences in Between Silk and Cyanide: A Codemaker's War 1941-1945. Marks was also a screenwriter. His most famous film was the 1960's cult-classic Peeping Tom.