I. Introduction -- II. Theory and Methods. 2. Review of Demand Analysis. 3. Concepts of Welfare Change. 4. Measuring Welfare Changes. 5. A Convenient Parametric Approach. 6. Equivalent Incomes and Optimal Taxation -- III. Applications. Marginal Tax Reform. 7. Marginal Tax Reform. 8. Indirect Tax Reform. 9. The Distributional Effects of Inflation. 10. Welfare Costs of Monopoly. 11. Carbon Taxation and Welfare