Karl Marx, a German philosopher, economist, and revolutionary, developed influential theories on class struggle, historical materialism, and the critique of capitalism, notably in The Communist Manifesto and Das Kapital. His views emphasized the inherent conflict between the working class (proletariat) and the owning class (bourgeoisie) in capitalist societies, predicting capitalism's eventual downfall and replacement by socialism, then communism. His ideas fueled significant 20th-century political movements, inspiring variants like Leninism and Maoism. Marx remains a foundational figure in modern social science and socialist theory.
