The Russian tragedy

What went wrong in Russia? How did the successful attempt to overthrow the old dictatorship of the Tsarist system only lead to the new dictatorship of the Communists? Alexander Berkman's work The Russian Tragedy is key to understanding these questions, since Berkman supported the revolution that overthrew the Tsar. He arrived in Russia at the beginning of 1920, having been deported from the United States because of his opposition to the First World War. Less than two years later he left Russian, convinced that the Communists had destroyed the social revolution he had spent his life fighting for.