Stalin was a Communist who ruled the Soviet Union from 1929 until 1953. He was known to relieve or kill top ranking officials in the Soviet government if he did not like them. He has been compared to Adolf Hitler for ruthlessness. Stalin also killed millions like Hitler when farmers called "kulaks" would not give up their land to the government for collectivization. His reign is marked by thousands of deaths of his fellow countrymen who were killed for resisting his regime. Leon Trotsky wrote in his book The Revolution Betrayed that Stalin and his regime contradicted all the theories of Marxist Communism.