When writers on economics are preparing their chapters on the production of wealth they keep in mind the chapters on the distribution of wealth which they are to prepare later and try to secure a conformity of treatment between the two parts. As a result of this search for conformity it has been found convenient to recognize four factors or agents in production and to make a corresponding fourfold division of income in the field of distribution. Thus, instead of speaking of nature and man as the two factors in production, we speak of land, labor, capital, and business enterprise as the four factors, and when we come to study distribution we shall learn to classify the respective shares as rent, wages, interest, and profits.