The Double-Cross System The Classic Account of World War Two Spy-Masters

Written as an official report for MI5 in 1945, originally published with the permission of the British Government over twenty years later, The Double-Cross System details the Allied handling of enemy agents and the British infiltration of Nazi spy-rings.
Telling the stories of the agents codenamed Zigzag, Tricycle, Garbo and Snow, Masterman also tells the story of a triumphant operation in the Second World War's intelligence effort.