The Bolshevik leader who organized the October Revolution, founded the Soviet state, and created the organizational model — the vanguard party, democratic centralism, and one-party rule — that defined communist movements worldwide for the remainder of the 20th century.
Lenin did not discover Marxism. He didn't write its founding texts or lead its mass movements. What he did was solve a problem Marx had left open: how do you actually make a revolution? His answer — a disciplined professional party, centralized command, absolute ideological unity, seizure rather than waiting — was so effective it reshaped global politics for a century. The question his career forces is whether the tools of seizure can be put down once power is won.