Karl Marx was commissioned by the Communist League along with Friederich Engels to write The Communist Manifesto. The manifesto is considered to be one of the world's most influential political tracts. The Manifesto established a course of action for the working class revolution to overthrow the bourgeois social order and bring about a classless society. In 1859 Marx published A Contribution To The Critique Of Political Economy, which was his first serious economic work. Marx discusses the production and naturalization of capitalism. His theory is that the course of history is dependent on economic developments. From the preface "In the social production that men carry on, they enter into definite relations that are indispensable and independent of their will, relations of production which correspond to a definite stage of development of their material forces of production. The sum total of these relations of production constitutes the economic structure of society, the real foundation, on which rises a legal and political superstructure, and to which correspond definite forms of social consciousness. The mode of production in material life determines the general character of the social, political, and intellectual processes of life. It is not the consciousness of men which determines their existence; it is on the contrary their social existence which determines their consciousness."