In the book The Origin of the Family, Private Property, and the State (1884), which, as Lenin pointed out, is of such importance for the Marxist world-view, Engels notes that he had written this work to some extent as a completion of Marx's message. The scientific foundation of the book was the work by the American anthropologist and archeologist L. Morgan, who studied the kinship ties among the
... [Show full abstract] North American Indians and some aspects of ancient Greek, Roman and German history. Engels added many of his own studies of the ancient Germans and Celts to Morgan's material, after having reformulated Morgan's economic arguments.