[Note to the American Edition: According to some criticisms of my book it should have been my task not only to give a sketch of the economic theory of Marx, but also to prove it “in extenso” and to refute the criticisms of it, since it is not universally accepted. It is true that this theory has not been generally accepted—a thing that would be impossible from the social consequences of such acceptation—but I claim that of all the economic theories, that of Marx is the only one that daily wins more adherents, and more and more interpenetrates all social science—even in the case of authors who are the bitterest opponents of this theory. To require that a book like mine should once more set forth and defend the theory of Marx “in extenso”, is as impossible as to require that a modern biologist, who proceeds upon the basis of the Darwinian theory, should prove over again that his basis is sound. That there may be more or less error in detail in the theory of Marx, as in that of Darwin, is possible, but in general they have resisted, like a wall of bronze, all attacks in the most pitiless of contests, that of opinions. Let the adversaries of Marx’s theory judge without prejudice whether that theory does not constitute a great step in advance in criminology!] PART TWO. BOOK I. THE PRESENT ECONOMIC SYSTEM AND ITS CONSEQUENCES. CHAPTER I. THE PRESENT ECONOMIC SYSTEM. [267] In order to provide for his needs man has always been obliged to work, and this work has always depended upon the physical environment and especially upon the means of production. It is not our province to enquire how or why the means of production were developed. It is enough to show that because of their development the products which man had at his disposal were multiplied. Now when these products become too abundant for one group of producers, a surplus results, which may be exchanged for products of a different sort of which the first group of producers are deprived by reason of their circumstances. These products, which are not destined for personal use but for exchange are called commodities. Consequently it is its social qualities and not its natural qualities that make a commodity of any given product. That an exchange may be made, then, two conditions must be satisfied: First, There must have been a division of labor; for there would be no point in the exchange of identical products. The objects to be exchanged are those which have no immediate usefulness for the person who possesses them, while they are useful to those who do not possess them. Second, The persons who are exchanging must have full power to dispose of their products—in other words, they must be the possessors of the product which they wish to exchange.