Marx, Karl (1818-1883), German political philosopher and revolutionary, co-founder with Friedrich Engels of scientific socialism (modern communism), and, as such, one of the most influential thinkers in modern history.

Marx was born in Trier on May 5, 1818, and educated at the universities of Bonn, Berlin, and Jena. In 1842, shortly after contributing his first article to the Cologne newspaper Rheinische Zeitung, Marx became editor of the paper. Although his political views were radical he was not yet a communist. His writings in the Rheinische Zeitung criticizing contemporary political and social conditions embroiled him in controversy with the authorities: in 1843 Marx was compelled to resign his editorial post, and soon afterwards the Rheinische Zeitung was forced to discontinue publication. Marx then went to Paris. There, as a result of his further studies in philosophy, history, and political science, he adopted communist beliefs. In 1844, when Engels visited him in Paris, the two men found that they had independently arrived at identical views on the nature of revolutionary problems. They undertook to collaborate in a systematic elucidation of the theoretical principles of communism and in the organization of an international working-class movement dedicated to those principles. Their collaboration was to continue throughout Marx's life.