Vladimir Lenin, born Vladimir Ilyich Ulyanov, on April 22, 1870, in Simbirsk, Russia, was a revolutionary leader and a principal theorist of Marxism. His political theories, known as Leninism, built upon the works of Karl Marx, played a pivotal role in the establishment of the Soviet Union, and made a lasting impact on global politics. Lenin's intellectual contributions to Marxist theory include his analysis of imperialism as the highest stage of capitalism and his theorization of the vanguard party to lead proletarian revolution. Among his most significant works is 'The Proletarian Revolution and the Renegade Kautsky' (1918), a critical response to Karl Kautsky's views on socialism and a defense of the Bolshevik Revolution. Lenin's scathing critique exemplifies his ability to combine sharp rhetoric with a formidable theoretical framework, illustrating his unyielding commitment to proletarian struggle. His work is characterized by piercing analysis of class relations, revolutionary strategy, and insistence on the dictatorship of the proletariat as a necessary phase in the transition to communism. Lenin's life and work have been extensively studied and continue to be subject to debate, influencing a broad range of political ideologies and movements. His death on January 21, 1924, did not extinguish his influence, which persists in the foundations of modern socialist thought.