This book reports the authors'' research on one of the most sophisticated general equilibrium models designed for tax policy analysis. Significantly disaggregated and incorporating the complete array of federal, state, and local taxes, the model represents the U.S. economy and tax system in a large computer package. The authors consider modifications of the tax system, including those being raised in current policy debates, such as consumption-based taxes and integration of the corporate and personal income tax systems. A counterfactual economy associated with each of these alternatives is generated, and the possible outcomes are compared.