Vladimir Lenin was a Russian revolutionary and the leader of the Bolshevik Party, which played a crucial role in the October Revolution of 1917. He became the first head of the Soviet state and is known for his theories on Marxism, which he adapted to the Russian context, leading to the establishment of a one-party socialist state. Lenin's policies, including the New Economic Policy (NEP), aimed to rebuild the economy after the devastation of World War I and the Russian Civil War. His legacy is complex, as he is both celebrated for his role in establishing the Soviet Union and criticized for the authoritarian measures he implemented.