1. Introduction 2. The Duality Between Production and Cost Functions 3. Joint Cost Functions and Variable Profit Functions 4. Nonjointness and Separability 5. The GNP Function Approach to Modeling the Demand for Imports 6. The GNP Function Approach to Modeling the Supply of Exports 7. Functional Forms 8. Other Technical Issues 9. Aggregate Production and Revenue Functions 10. The Heckscher-Ohlin-Samuelson and the Specific-Factors Models 11. Production and the Demand for Imports 12. The GNP Function the Demand for Imports and the Supply of Exports in the Short Run and the Medium Run 13. The Translog GNP Function Further Empirical Issues 14. Alternative Functional Forms 15. Input Requirements of Output Components 16. Disaggregation of Imports 17. Disaggregation of Exports 18. Terms of Trade Tariffs and Welfare 19. Technological Change Terms of Trade. and Growth 20. Conclusions