In the preface to A Contribution to the Critique of Political Economy, published in Berlin, 1859, Karl Marx relates how the two of us in Brussels in the year 1845 set about:
"to work out in common the opposition of our view" -- the materialist conception of history which was elaborated mainly by Marx -- "to the ideological view of German philosophy, in fact, to settle accounts with our erstwhile philosophical conscience. The resolve was carried out in the form of a criticism of post-Hegelian philosophy. The manuscript, two large octavo volumes, had long reached its place of publication in Westphalia when we received the news that altered circumstances did not allow of its being printed. We abandoned the manuscript to the gnawing criticism of the mice all the more willingly as we had achieved our main purpose -- self-clarification!"
Since then more than 40 years have elapsed and Marx died without either of us having had an opportunity of returning to the subject. We have expressed ourselves in various places regarding our relation to Hegel, but nowhere in a comprehensive, connected account. To Feuerbach, who after all in many respects forms an intermediate link between Hegelian philosophy and our conception, we never returned.
In the meantime, the Marxist world outlook has found representatives far beyond the boundaries of Germany and Europe and in all the literary languages of the world. On the other hand, classical German philosophy is experiencing a kind of rebirth abroad, especially in England and Scandinavia, and even in Germany itself people appear to be getting tired of the pauper's broth of eclecticism which is ladled out in the universities there under the name of philosophy.
In these circumstances, a short, coherent account of our relation to the Hegelian philosophy, of how we proceeded, as well as of how we separated, from it, appeared to me to be required more and more. Equally, a full acknowledgement of the influence which Feuerbach, more than any other post-Hegelian philosopher, had upon us during our period of storm and stress, appeared to me to be an undischarged debt of honor. I therefore willingly seized the opportunity when the editors of Neue Zeit asked me for a critical review of Starcke's book on Feuerbach. My contribution was published in that journal in the fourth and fifth numbers of 1886 and appears here in revised form as a separate publication.
Before sending these lines to press, I have once again ferreted out and looked over the old manuscript of 1845-46 [The German Ideology]. The section dealing with Feuerbach is not completed. The finished portion consists of an exposition of the materialist conception of history which proves only how incomplete our knowledge of economic history still was at that time. It contains no criticism of Feuerbach's doctrine itself; for the present purposes, therefore, it was unusable. On the other hand, in an old notebook of Marx's I have found the 11 Theses on Feuerbach, printed here as an appendix. These are notes hurriedly scribbled down for later elaboration, absolutely not intended for publication, but invaluable as the first document in which is deposited the brilliant germ of the new world outlook.
FREDERICK ENGELS London February 21, 1888