Book excerpt: This study is the result of an interest in the economic theory of production intermittently pursued during the past three years. Over this period I have received substantial support from the Office of Naval Research, first from a personal service consulting contract directly with the Mathematics Division of the Office of Naval Research and secondly from Project N6 onr-27009 at Princeton Univer sity under the direction of Professor Oskar Morgenstern. Grateful acknowledgement is made to the ·Office of Naval Research for this support and to Professor Morgenstern, in particular, for his interest in the puolication of this research. The responsibility for errors and omissions, how ever, rests entirely upon the author. Professor G. C. Evans has given in terms of a simple total cost function, depending solely upon output rate, a treatment of certain aspects of the economic theory of production which has inherent generality and convenience of formulation. The classical approach of expressing the technology of production by means of a production function is potentially less restrictive than the use of a simple total cost function, but it has not been applied in a more general form other than to derive the familiar conditions between marginal productivities of the factors of produc tion and their market prices.