This paper presents the political activity of Leon Trotsky, the development of the theory of permanent revolution, Trotsky's conception of it and his predictions of the great Russian revolution that will change the course of history. Leon Trotsky is one of the most famous politicians and revolutionaries in Russian history. Born in a small village in Ukraine, he became fascinated with the ideas of socialism and revolution at a young age, becoming a member of social democratic societies. Because of his political activity, he was targeted by the authorities throughout his life, therefore he spent most of his life either in Siberia or in exile. Trotsky began to formulate his conception of the theory of permanent revolution at the beginning of the 20th century, inspired by Karl Marx and Friedrich Engels, who were the first to write about it. He presented different ideas and popularized the theory, so today the theory is mostly associated with his name. Although Trotsky was a good theorist, his predictions about the course of the revolution beginning in 1917 did not completely come true. Trotsky played a major role during the Russian revolution and the Civil War, and did everything to make his theory come true and establish socialism, even if it involved numerous victims of the Russian people. Because of his great influence and power, he became Stalin's main enemy, which ultimately cost him his life.