A Perfect Spy is set during the Cold War, a long period of tense rivalry that began in the immediate aftermath of World War II. The US and the Soviet Union were uneasy allies during the war, but once it was over, their ideological differences cast them as adversaries. The US and allies like Great Britain perceived the Soviet Union as a military and ideological threat to their stability, especially given that after the war, the Soviet Union installed several communist, left-wing, or non-capitalist governments in Eastern Europe. Capitalist countries feared the spread of communist ideology to Western Europe, while the Soviet Union feared that capitalist countries would seek to undermine its new governments. As such, the Cold War was a period of competition and tension between—in broad terms—the communist east and the capitalist west for ideological control.

The term Cold War refers to the absence of explicit conflict. The US, Great Britain, and the Soviet Union didn’t attack one another directly. Both sides had nuclear weapons—and, fearing the use of these weapons, neither directly attacked the other. Instead, the war was fought using propaganda, spying, economic sanctions, and other means, which occasionally spilled over into proxy battles between the sides, such as the Soviet invasion of Afghanistan (in which the Western countries funded and armed the opponents of the Soviets) or the US invasion of Vietnam (in which the Soviets funded and armed the North Vietnamese).