In consequence of periodical cycles and crises capitalist reproduction fluctuates as a rule around the level of the effective total demand of society, sometimes rising above and sometimes falling below this level, contracting occasionally even to the point of almost complete interruption of reproduction. However, if we consider a longer period, a whole cycle with its alternating phases of prosperity and depression, of boom and slump, that is if we consider reproduction at its highest and lowest volume, including the stage of suspension, we can set off boom against slump and work out an average, a mean volume of reproduction for the whole cycle. This average is not only a theoretical figment of thought, it is also a real objective fact. For in spite of the sharp rises and falls in the course of a cycle, in spite of crises, the needs of society are always satisfied more or less, reproduction continues on its complicated course, and productive capacities develop progressively. How can this take place, leaving cycles and crises out of consideration? Here the real question begins. The attempt to solve the problem of reproduction in terms of the periodical character of crises is fundamentally a device of vulgar economics, just like the attempt to solve the problem of value in terms of fluctuations in demand and supply. Nevertheless, we shall see in the course of our observations that as soon as economic theory gets an inkling of the problem of reproduction, as soon as it has at least started guessing at the problem, it reveals a persistent tendency suddenly to transform the problem of reproduction into the problem of crises, thus barring its own way to the solution of the question. When we speak of capitalist reproduction in the following exposition, we shall always understand by this term a mean volume of productivity which is an average taken over the various phases of a cycle. Now, the total of capitalist reproduction is created by an unlimited and constantly changing number of private producers. They produce independently of one another; apart from the observation of price fluctuations there is no social control--no social link exists between the individual producers other than the exchange of commodities. The question arises how these innumerable disconnected operations can lead to the actual total of production. This general aspect of our problem indeed strikes us immediately as one of prime importance. But if we put it this way, we overlook the fact that such private producers are not simply producers of commodities but are essentially capitalist producers, that the total production of society is not simply production for the sake of satisfying social requirements, and equally not merely production of commodities, but essentially capitalist production.