The pantheon of world-changing spies is small and select, and Oleg Gordievsky is in it: he opened up the inner workings of the KGB at a pivotal juncture in history, revealing not just what Soviet intelligence was doing (and not doing), but what the Kremlin was thinking and planning, and in so doing transformed the way the West thought about the Soviet Union. He risked his life to betray his country, and made the world a little safer. As a classified internal CIA review put it, the ABLE ARCHER scare was “the last paroxysm of the Cold War.”