From Wikipedia


Cold War

Episode Twenty One

Spies

Cold War espionage describes the intelligence gathering activities during the Cold War between NATO and the Warsaw Pact. Because each side was preparing to fight the other, intelligence on the opposing side's intentions, military, and technology was of paramount importance. To gather this information, the two relied on a wide variety of military and civilian agencies. While several such as the CIA and KGB became synonymous with Cold War espionage, many other organizations played key roles in the collection and analysis of a wide host of intelligence disciplines.

During World War II the various allied nations held a tenuous relationship with the Soviet Union, but cooperation persisted due to a common enemy. Never quite trustful of each other, this resulted in espionage of tactics and technology between the Western bloc and Soviet bloc. After World War II ended, the two sides became increasingly confrontational, culminating in the Cold War.