The authors, two Russian historians, collected the most interesting quotations of famous Russian thinkers of the 20th centuries about the revolution of 1917 and bolshevism as an ideology and social system. These thoughts about the essence of bolshevism were arranged into the following chapters: Social barbarism and the cultural degradation of Russia; Domination of the worst; Underground and criminal system; Bolshevism as a reproduction of Russian historical traditions and the Russian soul; Bolshevism as activization of Russia; Metamorphoses of Westernism and anti-Westernism; Communism as another version of capitalism; etc. Afterwords by the authors summarize the collected ideas.