Man has made his history not by a metaphorical evolution nor with a view of walking on a line of preconceived progress. He has made it by creating his own conditions, that is to say, by creating through his labor an artificial environment, by developing successively his technical aptitudes and by accumulating and transforming the products of his activity in this new environment. We have but one single history and we cannot compare real history, which is actually made, with another which is simply possible. Where shall we find the laws of this formation and of this development? The very ancient formations are not evident at first sight. But bourgeois society because it is born recently and has not yet reached its full development, even in all parts of Europe, bears within itself the embryonic traces of its origin and its _processus_, and it puts them in full evidence in countries where it is in process of birth before our eyes, as for example, in Japan. In so far as it is society which transforms all the products of human labor into commodities by means of capital, society which assumes the proletariat or creates it and which bears within itself the anxiety, the trouble and the uncertainty of continuous innovations, it is born in determined times according to clear methods which can be indicated although they may be varied. In fact in different countries it has different modes of development. In Italy, for example, it begins before all the others and then stops. In England it is the product of three centuries of economic expropriation of the old forms of production, or of the old proprietorship, to speak the language of the jurists. In one country it elaborates itself little by little combining itself with pre-existing forces, as was the case in Germany, and it undergoes their influences through adaptation; in another country it breaks its envelope and crushes out resistance violently, as happened in France, where the great revolution gives us the most intense and the most bewildering example of historic action that is known, and thus forms the greatest school of sociology. As I have already indicated this formation of modern or bourgeois history has been summed up in rapid and masterly strokes in the Manifesto, which has given its general anatomical profile with its successive aspects, the trade guild, commerce, manufacture and the great industry and has also indicated some of the organs and appliances of a derived and complex character, law, political forms, etc. The elements of the theory which was to explain history by the principle of the class struggle were already implicitly contained in it. This same bourgeois society which revolutionized the earlier forms of production had thrown light upon itself and its _processus_ in creating the doctrine of its structure, economics. In fact it has not developed in the unconsciousness which characterized primitive societies but in the full light of the modern world beginning with the Renaissance.