Behind the Cold War an unseen war was waged for half a century, between the secret services of East and West. By definition, this other war was invisible to the public, although at times aspects of it would burst into public view. In regular contact with Britain's SIS (MI6) and consultant to the Foreign Office's semi-secret, anti-subversion department, IRD, and to the CIA, Brian Crozier not only witnessed the unseen war from the inside, but also played an active role in it. At all times, however, he retained his freedom of action: hence the title, "Free Agent". This account of the unseen war is part autobiography, part informal history. It throws a light on the events of five troubled decades and shows how, in the last analysis, the West did not "win" the Cold War: the Soviet side lost it.