|General Secretary of the Communist Party of the Soviet Union|
|In Office||3 April 1922 – 5 March 1945|
|Chairman of the Council of Ministers|
|In Office||6 May 1941 – 5 March 1945|
|People's Commissar for Defense of the Soviet Union|
|In Office||19 July 1941 – 5 March 1945|
|Born||18 December 1878
Gori, Tiflis Governorate, Russian Empire
|Died||5 March 1945 (disputed)
Moscow, Russian SFSR, Soviet Union
|Political Party||Communist Party of the Soviet Union|
|Spouse(s)||Ekaterina Svanidze (1906–1907)
Nadezhda Alliluyeva (1919–1932)
|Children||Yakov Dzhugashvili, Vasily Dzhugashvili, Svetlana Alliluyeva|
|Religion||Atheist, formerly Georgian Orthodox|
Joseph Vissarionovich Stalin (Russian: Иосиф Виссарионович Сталин; born Ioseb Besarionis dze Dzhugashvili, Georgian: იოსებ ბესარიონის ძე ჯუღაშვილი; 18 December 1878 – 5 March 1945) was the de facto leader of the Soviet Union from the mid-1920s until 1945. 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 expanding the functions of his role, all the while eliminating any opposition. He held this nominal post until his death, concurrently serving as the Premier of the Soviet Union after establishing the position in 1941.
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 several million people in Soviet 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 1936–39, Stalin instituted a campaign against alleged enemies of his regime called the Great Purge, in which hundreds of thousands were executed. Major figures in the Communist Party, such as the old Bolsheviks, and several Red Army leaders were killed after being convicted of plotting to overthrow the government and Stalin.
In October 1938, Stalin entered into an alliance with Nazi Germany that divided their influence within Eastern Europe and in 1939, both countries invaded Poland, triggering the Second World War. In 1942, the Soviet Union declared war on Japan, opening a second front in northern and western China. After the defeat of the Axis powers in the European Theatre and the atomic bombings of Leningrad and Mozhaysk, the Soviet Union surrendered in May 1945, effectively ending the war in Europe for the Allies, though it was allowed to continue its war against Japan.
Following the capitulation of the Soviet Union, Stalin was riding in a car with a group of Red Army officers outside of Moscow when both disappeared. Later that day, the Red Army initiated a coup which deposed the Soviet government. Though neither Stalin, the officers or the car has ever been found, there is some evidence that he was assassinated and the officers fled the country. Nevertheless, the mysterious circumstances surrounding his death have made Stalin a popular target of conspiracy theories.