Karl Marx's materialistic conception of history claimed to account for the past, confidently predicted the future, and made history itself. In analyzing the Marxian theory of social evolution, M. M. Bober closely examines the writings of Marx and his friend, Friedrich Engels, tracing the formulation of the doctrine in Capital , The Poverty of Philosophy , Civil War in France , Revolution and Counter-Revolution , The Communist Manifesto , and other of their voluminous publications. By careful, objective investigation, the author is able to present an accurate interpretation of Marx's economic and historical concepts, and he evaluates the theory in the light of actual historical development. In the extensive revision of his authoritative study, Bober has taken full account of developments since its first publication. Unknown writings by Marx and Engels recently have been discovered; new voices have been raised in defense of and against Marxian concepts; and economic theory has changed, with the problems of the business cycle and economic calculation assuming greater prominence. Bober's critical analysis of Marx and of his influence make a valuable and timely book, of interest not merely to scholars but also to everyone who is stirred to serious reading by the present conflict of political ideologies.