Suppose Congress were to change Social Security just before you retired? Or repeal income tax deductions for homeowners? Or institute a flat tax? Should those changes be retroactive? Or should you retain the gains or accept the losses resulting from the new enactments? What kinds of policies might governments adopt in order to mitigate the transitional effects of changing legal rules? Daniel Shaviro tackles these tough questions, bringing legal, economic and political perspectives to bear on a persistent problem not often given serious attention. When Rules Change: an Economic and Political Analysis of Transition Relief and Retroactivity focuses on tax law changes to develop an in-depth understanding of the transitional issues inherent in any substantive rule change and also to advance a set of normative policy guidelines applicable to any such circumstance. Shaviro reframes traditional approaches to the problem of retroactivity and offers new insights into both the theory and policy of legislative transitions.