Berlin Game

Berlin Game begins with a plea from "Brahms Four," one of Britain's most valuable agents stationed in East Germany: He wants to cross the Iron Curtain and come to the West. Bernard Samson, the former field agent now stationed in London, is tasked with the rescue. But before he even sets out on the mission, suspicions arise that there is a traitor in the MI6, likely one of his closest colleagues.
The first in Deighton's acclaimed Game, Set, Match trilogy featuring the talented yet jaded intelligence officer Bernard Samson, Berlin Game is a riveting story of betrayal and suspicion in the Cold War.