Both superpowers and their respective allies stood face to face, and the possibility of nuclear war was seemingly only a breath away. In such a situation, gaining "the inside track" -- obtaining insights into what the other side was doing -- took on a crucial importance.
"Undercover" is the word which signals the essential duality of a spy's life. That person is not what he or she appears to be. Every smile, every gesture, every question masks a deeper, hidden reality.
Hence the moral twilight which has always surrounded spying. The person who is a brave hero, or heroine, to the one side, is a traitor to the cause on the other side.
This duality is illustrated by the lives of two famous members of the profession, one a Pole, Ryszard Kuklinski, and the other a German, Johanna Olbricht, both of whom died this month.
Polish Colonel Ryszard Kuklinski passed Warsaw Pact military secrets to the American Central Intelligence Agency (CIA) for more than a decade.
When he died in the United States last week at the age of 72, CIA director George Tenet paid glowing tribute to Kuklinski's contribution. He called him a "true hero of the Cold War" to whom all owed "an everlasting debt of gratitude."
Tenet said that it is "in great measure" due to the bravery and sacrifice of Colonel Kuklinski that his native Poland and the other nations of Central and Eastern Europe are now free.
As Alexander Smolar, the head of the Stefan Batory Foundation, a Warsaw research institute, puts it, "His case was one of the most dramatic and divisive issues in public debate in Poland, and thus was very interesting. By some political forces, and by some people, he has been presented as a national hero. One journal referred to him by the title of the 'first Polish soldier in NATO.'"
Of course, the affair looked different from the perspective of Marxist Warsaw. The Communists sentenced Kuklinski in absentia to death for treason in 1984. He had been spirited out of Poland with his family in 1981 shortly before the government there imposed martial law.
The sentence remained on the books in democratic Poland until 1995, six years after the fall of communism. And it took a further two years before Kuklinski was fully rehabilitated.
Analyst Miraslava Grabowska of Warsaw University's Institute of Sociology, probing the reason for the slow rehabilitation, says the communist condemnation of Kuklinski at the time was very strong, and probably influenced the thinking of the Polish public.
"The official position was that what he did was wrong, because there is a kind of loyalty not only to the political system, which was communist of course, but also to the political community and perhaps to colleagues, soldiers, [et] cetera -- so that he breached not only ideological loyalty, but also national loyalty and even group loyalty," Grabowska said.
Grabowska cites a survey of public opinion by the Polish media this week that indicates those attitudes are now changing.
"Forty-nine percent of the Polish population [perceives] him as a hero, 25 percent as a traitor, and 26 percent answered that it is difficult to say. So I think that after some period of hesitation or uncertainty on how to interpret his activity, right now, the positive evaluation of his activities prevails," Grabowska said.
Analyst Smolar says that the Kuklinski case is one which still touches a nerve in the national psyche, mirroring the still-unresolved feelings of Poles toward their recent history.
"Attitudes toward the case of Kuklinsky were extremely complex and painful, just as the attitudes of Poles were -- and still are -- complex and painful toward the Poland of today and to Poland of the past, communist Poland," Smolar said.
The other spy, Johanna Olbricht -- or Sonja Lueneburg, as she was known -- worked for communist East Germany from 1969 until into the 1980s.
She managed to become the chief secretary of Martin Bangemann, the Free Democrat politician who eventually rose through the ranks to become West Germany's economy minister, a top cabinet post.
After years of passing documents to the east, Olbricht was eventually recalled to East Germany, where she was feted and decorated by the regime.
But then, just a few years later, the Soviet and Marxist world began to crumble, and like many others, Olbricht found herself facing a new reality which did not find her spying efforts heroic.
She was convicted of espionage in 1994 by a court in a united Germany, and sentenced to two and a half years in prison.
However -- in another indication of the ambiguity of the situation -- the verdict was amended in 1996 to a suspended sentence. She died on 18 February at the age of 78.