Is an introduction to public policy aspects of tax systems, with emphasis on issues raised by contemporary proposals for tax reform. Many of the issues and arguments are multi-disciplinary, drawing upon economics, moral philosophy, political theory, history and psychology, among other fields of study. The methods, pre-occupations, and strengths of these disciplines are examined in detail. The course gives special attention to the following topics: how taxes affect individuals' welfare and behavior; what attributes of taxpayers should be taken into account for tax fairness; whether a broad tax based on income or one based on consumption is to be preferred; how taxes and public debt interact; whether, and if so how, business entities should be taxed separately from individuals; the goals and limitations of international tax policy; federalism in state and local taxation; the use and abuse of economic models. Knowledge of economics, philosophy, and the other fields mentioned is not a prerequisite.