It was in truth a work of genius. Immediately after the event that struck the whole political world like a thunderbolt from the blue, that was condemned by some with loud cries of moral indignation and accepted by others as salvation from the revolution and as punishment for its errors, but was only wondered at by all and understood by none-immediately after this event Marx came out with a concise, epigrammatic exposition that laid bare the whole course of French history since the February days in its inner interconnection, reduced the miracle of December 2 to a natural, necessary result of this interconnection and in so doing did not even need to treat the hero of the coup d' tat otherwise than with the contempt he so well deserved. And the picture was drawn with such a master hand that every fresh disclosure since made has only provided fresh proofs of how faithfully it reflected reality. This eminent understanding of the living history of the day, this clear-sighted appreciation of events at the moment of happening, is indeed without parallel. But for this, Marx s thorough knowledge of French history was needed. France is the land where, more than anywhere else, the historical class struggles were each time fought out to a decision, and where, consequently, the changing political forms within which they move and in which their results are summarised have been stamped in the sharpest outlines. The centre of feudalism in the Middle Ages, the model country of unified monarchy, resting on estates, since the Renaissance, France demolished feudalism in the Great Revolution and established the unalloyed rule of the bourgeoisie in a classical purity unequalled by any other European land. And the struggle of the upward-striving proletariat against the ruling bourgeoisie appeared here in an acute form unknown elsewhere. This was the reason why Marx not only studied the past history of France with particular predilection, but also followed her current history in every detail, stored up the material for future use and, consequently, events never took him by surprise. In addition, however, there was still another circumstance. It was precisely Marx who had first discovered the great law of motion of history, the law according to which all historical struggles, whether they proceed in the political, religious, philosophical or some other ideological domain, are in fact only the more or less clear expression of struggles of social classes, and that the existence and thereby the collisions, too, between these classes are in turn conditioned by the degree of development of their economic position, by the mode of their production and of their exchange determined by it. This law, which has the same significance for history as the law of the transformation of energy has for natural science - this law gave him here, too, the key to an understanding of the history of the Second French Republic. He put his law to the test on these historical events, and even after thirty-three years we must still say that it has stood the test brilliantly.
Preface to The Eighteenth Brumaire of Louis Bonaparte by Engels 1885