In a brilliant feat of literary detective work Master of Lies tells the extraordinary untold story of Anthony Blunt's life as a spy. Based on extensive research into newly released files he is revealed as not simply "the fourth man", but the most dangerous spy of the twentieth century.

During the war, as the fate of the world hung in the balance, Blunt's intelligence was being fed straight on to the desks of Hitler, Stalin and Churchill. His hand was secretly guiding our collective fate and his treason led to the deaths of tens of thousands. He casts a shadow which looms large to this day.

The official narrative is that Blunt was the least of the Cambridge spies - and yet he was the one who got away with it. While the rest drank themselves to death in dingy Moscow flats, Blunt revelled in his brilliant career as an art historian, Surveyor of the Queen's pictures and Knight of the Realm. He was protected not just by his many friendships with the great and the good, but by the brilliance with which he played the game - his was a secret too big to be told.

Master of Lies reads like the best spy fiction but it solves one of the great espionage mysteries of our times.