Most World War II spies learned little of import—and those who did were invariably disbelieved.

Any historian who hopes to tell the true story of secret intelligence operations, even from the distant past, quickly discovers that he is up against two formidable obstacles.

First is the Kafkaesque system of government classification. Not only do U.S. intelligence agencies routinely refuse to declassify material from 70 or more years ago, they have taken to reclassifying and removing from the National Archives some previously released World War II-era files.

The other problem is that spies are professional, if not congenital, liars.

In the introduction to his sprawling, revisionist-tinged history of espionage, cryptanalysis, and partisan warfare in World War II, British historian Max Hastings quotes the cautionary words of Malcolm Muggeridge, who worked for the British secret service during the war. Intelligence work, Muggeridge said, “necessarily involves such cheating, lying, and betraying that it has a deleterious effect on the character. I never met anyone professionally engaged in it whom I should care to trust in any capacity.”

The field of intelligence history accordingly “generates a vast, unreliable literature,” Mr. Hastings notes. The years after World War II brought a spate of memoirs recounting daring escapades behind enemy lines, many of which existed only in the writers’ imaginations but which still shape perceptions about the role of the spies and saboteurs of America’s Office of Strategic Services, Britain’s MI6 and Special Operations Executive, and the French Resistance.

Inside the Oscar-winning movie, The Imitation Game, in Bletchley Park’s stunning exhibition.The exhibition is staged in the rooms within the iconic Victorian Mansion where key scenes were filmed.The biopic of Bletchley Park Codebreaker Alan Turing opened in cinemas in November 2014 and stars a host of British acting talent including Benedict Cumberbatch and Keira Knightley. – Bletchley Park

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Featured Image –Bletchley Park, The Bombe and its WRNS Operators in Hut 11