The following collections include insights into the nature of and controversies surrounding the Bolshevik Revolution. If you are interested in how Russia turned Communist, give them a quick (or deeper) look.
Russian Revolution Primary Source I
A reading on the theory and practice of Bolshevism, Vladimir Lenin, "What is to be Done?" (1902)
Alongside Germany's Adolf Hitler, Stalin is usually included atop any list of 20th century bad guys. The following sources explore Stalin's tactics in modernizing Soviet industry and maintaining totalitarian control over the largest and perhaps most repressive state of its time. The final collection includes rebukes of Stalin's methods, but it's important to note that no one rebuked Stalin until after he died.
Stalinism Primary Sources I
Three Readings on the U.S.S.R.'s need to "Modernize or Perish" and "Collectivization"
Read several brief selections from Hitler's Mein Kampf, in which he pretty much told the world what he was about, and they chose not to listen. Still a better love story than Twilight but nevertheless depressing.