Garbo, Brutus, Treasure, Fuchs, Gold, Penkovsky ...these names probably mean nothing to you, and yet those who carry them have contributed to changing the course of history in the greatest secrecy. Whether it was because of ideology, the lure of something exciting, or simply because they had no choice, these men and women were the greatest spies of the Second World War and the Cold War. They worked in the shadows for years on behalf of the CIA, MI-5, or the KGB. They stole top-secret documents, leaked false information, created false identities, uncovered «moles» ... and they played crucial roles in some of the most im- portant moments of the 20th century.