In 1991, Communist rule in the Soviet Union came to an end after 84 years, and the world's largest state, one of the two global superpowers, broke up into fifteen independent countries. Few had predicted such an outcome when Mikhail Gorbachev became the leader of the Soviet Union six years before. Jeremy Smith discusses the long-term and short-term factors behind this extraordinary collapse, assessing the impact of economic crisis, nationalism, personalities and democratization in the process.