I. Introduction, 129. — II. The production possibility with interindustry flows and substitutable primary factors, 130. — III. A two-product diagrammatic illustration, 132. — IV. The marginal rate of transformation along the input-output opportunity cost curve, 133. — V. The generalized theory of factor-price equalization, 135. — VI. Real wage, income distribution and the terms of trade, 138. — VII. The generalized factor-proportions theory of international trade, 139. — Appendix, 141.