Biographical study of a man claimed to be the most successful spy ever to operate within Australia, written by an acknowledged expert on the world of espionage and author of the influential study TThe Secret State' (1978). Explores the life and career of Ian Milner, an Oxford scholar who was employed during the 1940's in a senior position in the Foreign Affairs Department and who defected to the East in 1950. The links between Milner's defection and the Petrov case are also examined.