The competition with Germany and its intelligence services preoccupied MI5 through World War II.
The famed "double cross" operations against the Third Reich and its Abwehr probably represented the Security Service's finest hour -- and one of the most complete triumphs by any intelligence agency in time of war.
Andrew's account of MI5's masterful deception operations reads like one of the multitude of spy novels they inspired.
At the same time, his account of Anthony Blunt, Kim Philby, Guy Burgess and Donald Maclean -- the so-called Cambridge spies who betrayed U.K. and U.S. intelligence to the Soviets -- is unsparing and adds enlightening detail to ground frequently and painfully plowed. (In regard to more recent events, particularly MI5's counter-terrorist operations against the Provisional IRA, Andrew's material is sketchier and less satisfying.)
When it comes to Blunt, Philby et al., Andrew demonstrates just how adroitly the Soviets played on the clubby, inbred culture of MI5, which until 1997 relied entirely on personal recommendations for recruitment -- consciously excluding women and Jews.