This book is devoted to a question closely connected with the history of three Russian revolutions—but not only with them. In recent years, this question played a huge role in the internal struggle of the Communist Party of the Soviet Union. Then it was brought to the Communist International, played a decisive role in the development of the Chinese revolution, and influenced a whole series of decisions of the highest importance related to the revolutionary struggle of the Eastern countries. The matter concerns the so-called theory of “permanent revolution,” which, according to the epigones of Leninism (Zinoviev, Stalin, Bukharin, etc.), constitutes the original sin of “Trotskyism.”