Eleven years after the publication of the Manifesto, Marx formulated in clear and precise fashion the directing principles of the materialistic interpretation of history in the preface to a book which is the forerunner of "Capital."[11] "The first work which I undertook for the purpose of solving the doubts which perplexed me was a critical re-examination of Hegel's Philosophy of Law. The introduction to this work appeared in the German-French Year Books, published in Paris in 1844. My investigation ended in the conviction that legal relations and forms of government cannot be explained either by themselves or by the so-called general development of the human mind, but on the contrary, have their roots in the conditions of man's physical existence, whose totality Hegel, following the English and French writers of the eighteenth century, summed up under the name of civil society; and that the anatomy of civil society must be sought in political economy. The study of the latter which I began at Paris was continued at Brussels whither I had betaken myself in consequence of an order of Guizot expelling me from France. The general result which I arrived at and which, once obtained, served as a guide for my subsequent studies, can be briefly formulated as follows: In making their livelihood together men enter into certain necessary involuntary relations with each other, industrial relations which correspond to whatever stage society has reached in the development of its material productive forces. The totality of these industrial relations constitutes the economic structure of society, the real basis upon which the legal and political superstructure is built, and to which definite forms of social consciousness correspond. The method of producing the material livelihood determines the social, political and intellectual life process in general. It is not men's consciousness which determines their life; on the contrary, it is their social life which determines their consciousness. At a certain stage of their development the material productive forces of society come into conflict with the old conditions of production or, to use a legal expression, with the old property relations under which these forces have hitherto been exerted. From forms of development of the productive forces these relations turn into fetters of production. Then begins an epoch of social revolution. With the change of the economic basis the whole vast superstructure undergoes sooner or later a revolution.