It cannot be denied that Lenin was a staunch follower of Karl Marx but he was a dynamic and not an orthodox follower. He had to interpret Marxism in changed conditions and adapt them to Russia which was purely an agricultural country and where capitalism had not fully developed.
Lenin put emphasis on the revolutionary aspect and not the peaceful aspect of Marxism. He followed the teachings of Marxism as put-forth in the ‘Communist Manifesto’ and ‘Das Capital’ because he had unflinching faith only in the revolutionary methods.
He thought rightly that the revolution in Russia could not be brought about by peaceful means because before him, Tolstoy had advocated peaceful means and nothing had been achieved by them. He firmly believed that transition from capitalism to communism could not be brought about by pacific means.That is why he condemned Kautsky and others of their way of thinking. He believed in a revolution and not in allowing the events to drift according to the sweet wishes of Czar Nicholas II (then Emperor of Russia).
While Marx had emphasised the development of self-consciousness amongst the workers due to extreme economic misery, Lenin thought that revolution could be brought about in Russia only by the disciplined and secret cadre of the Communist Party which could infiltrate and arouse the strong political consciousness against the tyrannical regime of Czar amongst the peasants, workers, soldiers, the police, the students and government servants.
By using all these methods, Lenin was able to overthrow the Czarist regime and establish first socialist state of the world in Russia. Stalin consolidated it and was able to help Mao-tse-Tung, Communist leader of China in bringing about the revolution in 1949 and overthrow the reactionary regime of Chiang Kai-Shek.
After the Second World War (1939-45), former U.S.S.R. was able to extend communism to most of the countries of Eastern Europe (Poland, Hungary, Rumania, Bulgaria, Czechoslovakia and East Germany). Communism had also spread to former Yugoslavia, Vietnam and North Korea. So nearly half of the world had become communist due to teaching of Marxism-Leninism.