They were the top spymasters in the Third Reich, two rivals who were shrouded in mystery and sworn to secrecy. With thousands of agents at their command, they were entrusted with Germany's most sensitive intelligence operations in World War Two. In the end, one man would kill for Hitler, the other would betray him.

They were the English spies before James Bond. They operated in the shadows with innocuous names like the Special Operations Executive, MI-5 and MI-6, but their missions were deadly serious. Amazing facts that are stranger than fiction in the storied history of Britain's intelligence service during the Second World War.

This is the story of America's code-breaking efforts against seemingly impenetrable secret Japanese military and diplomatic communications and the heroic struggle of army code-breakers, headed by William Friedman, and the navy's secret on-the-roof-gang to help win the Battle of the Pacific.

They were the stuff of fantasy and terror, instruments of sabotage and clandestine operations. Born of great desperation and used under the cover of darkness, special tools of spies and espionage agents delivered war to the heart of the enemy on the invisible battleground.

They were unlikely heroes who fought behind enemy lines in every theatre of World War II. Female spies unearthed secrets, supported the resistance and destroyed the morale of the enemy. From women OSS agents dropped behind enemy lines to female radio operators inside the Third Reich, women played a decisive intelligence-gathering role in the war.

They were five disillusioned young men studying at Cambridge University in the 1930s when they were secretly recruited by Soviet agents. They went on to become the most successful spies of the 20th century, penetrating both American and British governments at the highest levels.

These are the Kremlin operatives who were loyal to one man, a paranoid dictator who spied as intensely on his Allies as he did on his enemies. Features exclusive interviews with former NKVD intelligence officers and other eyewitnesses to the most ruthless dictator of the 20th century.

This is the story of the formation of the predecessor to the CIA. From the recruitment and training of secret agents to undercover missions, OSS agents played an important role on the invisible battlefield in WWII.

Details the American President's behind the scenes use of political and military intelligence operatives. From O.S.S. chief William Donovan to the wily Switzerland-based Allen Dulles, American spymasters helped Roosevelt keep an eye on his enemies, as well as his friends.

It was the greatest secret of World War Two, the time and place of the D-Day invasion. As the future of Europe and the world hung in the balance, an intricate web of lies tied up German army divisions across Europe, concealing the greatest assembly of men and machines in military history. From double agents to phantom armies, it was the battle behind the battle.