Joseph Stalin

Among the Bolshevik revolutionaries who took part in the Russian Revolution of 1917, Stalin was appointed general secretary of the party's Central Committee in 1922. He subsequently managed to consolidate power following the 1924 death of Vladimir Lenin through suppressing Lenin's criticisms and expanding the functions of his role, all the while eliminating any opposition. By the late 1920s, he was the unchallenged leader of the Soviet Union. He remained general secretary until the post was abolished in 1952, concurrently serving as the Premier of the Soviet Union from 1941 onward.

Under Stalin's rule, the concept of "socialism in one country" became a central tenet of Soviet society. He replaced the New Economic Policy introduced by Lenin in the early 1920s with a highly centralised command economy, launching a period of industrialization and collectivization that resulted in the rapid transformation of the USSR from an agrarian society into an industrial power. However, the economic changes coincided with the imprisonment of millions of people in correctional labour camps and the deportation of many others to remote areas. The initial upheaval in agriculture disrupted food production and contributed to the catastrophic Soviet famine of 1932–1933, known as the Holodomor in Ukraine. Later, in a period that lasted from 1936 to 1939, Stalin instituted a campaign against alleged enemies within his regime, called the Great Purge, in which hundreds of thousands were executed. Major figures in the Communist Party, such as the old Bolsheviks, Leon Trotsky, and several Red Army leaders, were killed after being convicted of plotting to overthrow the government and Stalin.