Inessa Armand  -  A Bolshevik activist with whom Lenin became close friends during his years in Western Europe. It is unconfirmed whether the two had an affair, but her death in 1920 was a great blow to Lenin.

Lev Kamenev  -  A leading Bolshevik, and a member of Lenin's Politburo in the early '20s. He would be executed by Stalin in 1936.

Alexander Kerensky  -  A socialist (but not a Marxist), he became the leader of the Provisional Government in the summer of 1917, and fled to America after the Bolshevik coup.

Nadezhda Krupskaya  -  Lenin's wife, and a tireless Bolshevik activist, she assisted her husband throughout his rise to power.

Y.O. Martov  -  A prominent figure within the Social Democrats, he led the opposition to Lenin's proposal for a party of professional revolutionaries, and became the leader of the Menshevik faction.

Karl Marx  -  The 19th-century German intellectual who, in his philosophical work The Communist Manifesto, developed the theory that bears his name, Marxism.

Nicholas II - The last Tsar of Russia, executed with his family by the Bolsheviks in 1918.

Georgy Plekhanov  -  One of the founders of Russian Marxism, he worked with Lenin on the Marxist newspaper Iskra in the early 1900s, but eventually split with Lenin and came to ally himself with the Mensheviks.

Joseph Stalin  -  Born Iosef Vissarionovich Djugashvili, he took the name "Stalin," meaning steel, around 1912. A committed Bolshevik, he was part of Lenin's Politburo and a key figure in the Revolution and Civil War. After Lenin's death, he outmaneuvered his rivals and made himself master of the Soviet Union, which he ruled until his death in 1953. (For more information, see theSparkNote on Joseph Stalin.)

Leon Trotsky  -  A former ally of the Mensheviks, he joined the Bolsheviks before the Revolution and was responsible for organizing the Red Army and winning the Civil War. He was one of Lenin's favorites in the Politburo, but was outmaneuvered by Stalin, exiled in 1929, and assassinated in Mexico City in 1940 by one of Stalin's agents.

Alexander Ulyanov  -  Lenin's older brother. His arrest and execution in 1887, for conspiring to assassinate Tsar Alexander III, inspired Lenin to become a revolutionary.

Ilya Nikolayevich Ulyanov  - Lenin's father, Ulyanov was a prosperous government employee. During Lenin's childhood, he worked as an inspector of schools.

Maria Ulyanov  -  Lenin's mother

Grigory Zinoviev  -  A member of Lenin's Politburo, and a friend and ally of Kamenev. He would be executed by Stalin in 1936.

Bolshevik  -   · Literally, "majoritarian." The Bolsheviks were the group within the Social Democrats who supported Lenin's call for a party of professional revolutionaries. They orchestrated a takeover of the government during the Russian Revolution, and, calling themselves the Communist Party, came into total power.

Bourgeoisie  -   · "Bourgeois" is an adjective meaning "middle-class," and its noun form is "bourgeoisie." Marxists used these terms to denote the ruling class of the 19th century who exploited the proletariat.

Communist Party  -   · The name adopted by the Bolsheviks when they took power. As the Communist Party, they would rule the Soviet Union for seventy years.

Kulaks  -   · "Kulak" was a term devised by Lenin to describe the "wealthy" peasantry (though no real class divides existed within the peasantry). During the Red Terror, those unfortunate enough to be labeled "kulaks" had their property confiscated; when they resisted, they were killed in great numbers.

Marxism  -   · The revolutionary ideology upheld by Lenin and his fellow Bolsheviks. It predicted, "scientifically," the overthrow of capitalism, the abolition of private property, and rule by the working class, or proletariat.

Menshevik  -   · "Menshevik" means literally, "a member of the minority." The Mensheviks were the Social Democrats who, under the leadership of Martov, opposed Lenin after the 1902 split in their party.

Politburo -   · Originally, Lenin's inner circle in the 1920s. Later, it referred simply to the chief leaders of the U.S.S.R.

Proletariat  -   · In Marxist ideology, the working class, whose revolt against their bourgeois masters would usher in a classless society.

Provisional Government -   · The government that formed after Nicholas II's abdication, in March 1917. Led by Alexander Kerensky, it called for free elections and the creation of a Constituent Assembly to govern Russia, but it was overthrown by the Bolsheviks in November 1917.

Russian Social Democratic Labour Party  -   · Founded in 1898 as the first Marxist party in Russia, it eventually split into Menshevik and Bolshevik factions.

Russia  -   · A vast trans-continental nation and empire at Lenin's birth, it was theoretically subsumed into the Soviet Union along with the other constituent republics, but in practice dominated the U.S.S.R. politically.

Siberia  -   · The vast, frosty region, covering all of northeast Russia, where political prisoners were sent, both under the Tsars and under the Bolsheviks

Soviet Union  -   · Literally, a "soviet" referred a worker's council, like the Petrograd Soviet during the Revolution. The U.S.S.R. was the name that the Bolsheviks gave to their newly organized nation in 1922. It lasted until 1991.

Tsar  -   · A word derived from "Caesar." The Tsars were the Emperors of Russia before the Revolution.

Red Terror -   · This term was given to a campaign led during Russia's civil war, and was aimed at "counter-revolutionaries," usually found among the civilian population. It resulted in large-scale killings and the establishment of a system of concentration camps to hold political prisoners.

Civil War  -   · The period from 1918 to 1920, when the Bolsheviks, or "Reds," fought for control of Russia with the "Whites," a loose collection of armies united only by their opposition to Lenin and his comrades. Foreign armies from Britain, France, and America also intervened in the conflict on the side of the Whites, but the disunity and poor leadership of their enemies, as well as Trotsky's military genius, enabled the Bolsheviks to triumph.

New Economic Policy -   · Pursued by the Soviet Union from 1921 to 1927, this policy allowed the market economy to operate in rural areas. Lenin established the policy after the economic collapse and famine of 1921.

1905 Revolution  -   · The unrest that plagued Russia in 1905, following its defeat in the Russo- Japanese War and the massacre of protestors known as "Bloody Sunday." It forced Nicholas II to issue the "October Manifesto," in which he pledged to create an elected body, or "Duma," to assist him in governing Russia.

Russian Revolution  -   · This refers specifically to the events of 1917, when the Tsar's government fell, and the Bolsheviks came to power in Russia. Used more generally, it can describe the entire chaotic period from 1917 to 1920, including the years of civil war.

World War I  -   · This conflict (1914-1918) pitted Russia, Britain, and France (and eventually the U.S.) against Germany and Austro-Hungary. (See the SparkNote on World War I.) It was the stresses of World War I that led to the fall of Nicholas II's government in March 1917, and the coming of the Revolution.