German political philosopher and economist, resident in England from 1849. The founder of modern communism, he collaborated with Engels in the writing of the Communist Manifesto (1848). Thereafter Marx spent much of his time enlarging the theory of this pamphlet into a series of books, the most important being the three-volume Das Kapital. The first volume of this appeared in 1867 and the remainder was completed by Engels and published after Marx's death (1885; 1894). See Marxism.