Wikimedia
Wikipedia: Cheka
An explanation of what the Cheka was and the activities they engaged in to quell opposition under Lenin's rule.
Cato Institute
Cato Institute: Marxist Dreams and Soviet Realities
The CATO Institute, dedicated to "Individual Liberty, Limited Government, Free Markets and Peace, offers "Marxist Dreams and Soviet Realities" by Ralph Raico, originally published as Cato's Letter #2 in 1998 prior to the fall of the USSR.