The Yalta and Potsdam Conferences took place during and immediately after the Second World War, respectively. The three major Allied powers—Britain, the United States, and the USSR—met to discuss terms and the postwar world order. The Soviet Union was represented by Josef Stalin, who ruled the country at the time.

The Great Purge took place from the mid-1930s until 1940. It was an enforced program of political repression and was an attempt to consolidate power and control under Josef Stalin. Stalin ordered the Red Army purged of any subversive (or suspected subversive) elements, as well as the bullying and execution of millions of peasants.

The notion of a Five Year Plan is part of the Communist approach to controlled economies. During the history of the Soviet Union, the function of most five year plans was to either increase food production or to greatly improve industry and manufacturing. The first Five Year Plan was suggested by Stalin in the 1920s when he was still the General Secretary under Lenin. When Stalin assumed complete control of the party, he envisioned a system of collective farming across the nation and set up a Five Year Plan to engender this. It failed, somewhat spectacularly, and lead to grossly widespread famine and malnutrition.

In demanding an immediate transition to socialism for Russia, Lenin disagreed with Marx's views. Lenin also promoted the collectivization of farms, although at a more gradual rate than some of his peers. 

Lenin advocated revolution from above, by trained revolutionaries.

Vladimir Lenin implemented the New Economic Policy in 1921, to help stimulate the Soviet economy following the Russian Civil War. Josef Stalin abolished this policy when he took power in 1928, favoring much more rigid state control of the economy. Nikita Khrushchev kept much of this rigid state control in place. Mikhail Gorbachev launched economic reforms to liberalize the Soviet economy in the 1980s, but these reforms were not known as the New Economic Policy.

After the end of World War Two, the city of Berlin was divided into four zones of control: American, British, French, and Russian; however, the city itself was located in East Germany and thus under direct control of the Soviet Union. The American, French, and British sections were combined to form West Berlin. As the Cold War began to dominate global politics, the Soviet Union tried to control the entire city of Berlin and closed off the city to trade with the Western world. The French, British, and particularly American authorities, under the leadership of General Marshall, airlifted supplies into the Western areas of the city to keep the population from starving and also to keep them from turning in desperation to Communism.

The Eastern Bloc was established in the years immediately following World War Two when most of Europe was being divided between Western (American-influenced) Capitalism and Eastern (Soviet-influenced) Communism. Poland, East Germany, Romania, and Czechoslovakia were all incorporated into the Eastern Bloc under the Warsaw Pact. Finland and Switzerland were the only countries to remain neutral—neither Western- nor Eastern-aligned.

The Warsaw Pact was an agreement signed in 1955 between the various Eastern European and Soviet-bloc countries of the Cold War. It aimed to provide for mutual cooperation and defense and was essentially created as a foil to the American- and British-lead NATO Pact, which West Germany had joined the year before.

Yugoslavia is a somewhat unique case in the history of the Cold War in Europe. Although essentially a Communist nation, the government of Yugoslavia, led by Marshal Tito, sought to distance itself from Soviet hegemony. Tito was an ardent Yugoslavian nationalist.

The Truman Doctrine was the primary foreign policy of President Harry Truman in the years immediately after World War Two. The Truman Doctrine stated that the United States would provide economic and military aid to those countries facing a communist uprising to stop the spread of socialism and Soviet hegemony. The first two countries to be given American aid under the Truman Doctrine were Greece and Turkey, in 1947. Both countries were facing threats of Soviet hegemony and communist uprisings, so they were given financial and military support by the United States.