In this volume, a select group of UI researchers describes the motivation for and the design, implementation, and impacts of UI bonus experiments administered in Illinois, Pennsylvania, and Washington. They also describe the benefits and costs of the various experimental treatments for the government as a whole, the UI system in particular, claimants' earnings, and the overall net benefits to society. This volume analyzes experiments that are virtually unique for social policy research (i.e., multiple experiments with similar designs that enable comparison of results of experiments conducted in different locations and different social contexts), as well as the movement from experiment to policy by considering impacts on nonparticipants and explicit benefit-cost analysis.