In Spies Beneath Berlin, David Stafford, the widely recognized expert on World War II intelligence, tells the fascinating, in-depth account of one of the most audacious and intriguing covert operations of the Cold War: Operation Stopwatch/Gold. Called by CIA chief Allen Dulles, "one of the most valuable and daring projects ever undertaken," Operation Stopwatch/Gold was carried out from a secret tunnel half a mile long under the Russian sector of Cold War Berlin as, for more than a year, the CIA tuned into German Red Army intelligence. This was an almost impossible trick as, apart from the technical wizardry needed, any noise or vibration could have given the game away. Indeed, when snow fell, panic measures were suddenly needed to prevent it thawing in a tell-tale line leading to the target building. An added layer of complexity comes from the fact that Stopwatch/Gold was a joint CIA/MI6 project, and after Burgess and Maclean, it was clear that truth, even between allies, was dangerous.

Whether or not Operation Stopwatch/Gold was a success has been a point of contention over the years. For the first time, using eyewitness interviews and the full range of source material Stafford reveals the thrillingly complex story of this operation.