Tax systems have changed considerably in the past three decades. These fundamental changes have been the result of economic globalization, new political stances, and also of developments in public finance thought. The chapters in this volume offer a critical review of those changes from the perspectives of tax theory, policy and tax administration practice, and the political economy of taxation. The authors also consider what sort of reforms are worth undertaking in tax policy design, tax administration and enforcement, and the assignment of sub-national taxes.