The book of an English journalist tells the history of struggle between English and German counterintelligence at the first and the second world war times. 'There is no cease fire for the spies' - is the essence of a brought extensive documentary material. How these investigation bodies sprung up, how they acted at home and abroad: in the Near and Middle East, in Northern and Southern America, in Africa, in the countries of Europe - all this is submitted on pages of the book. But only facts! From methods of preparation and penetration of the agents up to the stories of Mata Khary, the admiral Canaris, the secret terrorist organization 'FEME', which the Nazi leaders used for elimination of their political opponents. Written in alive and extraordinary convincing form the Cookridge writing will interest undoubtedly not only professionals, historians and intelligence agents but also the wide circle of readers.