Proponents of 'nudge theory' argue that, because of our human susceptibility to an array of biases, we often make subprime choices and decisions that make us poorer, less healthy, and more miserable than we might otherwise be. However, using behavioural economics-and insights from other disciplines-they suggest that apparently small and subtle solutions (or 'nudges') can lead to disproportionately beneficial outcomes without unduly restricting our freedom of choice. Indeed, the apparently virtuous-and cost-effective-possibilities of nudge theory has led to its enthusiastic adoption by adherents in the highest echelons of government and business, and 'nudge units' (such as the Behavioural Insights Team in the British Cabinet Office) have been established in the UK, the United States, and Australia. While far from uncontroversial (some critics have questioned its ethical implications and dismissed many of its practical applications as short-term, politically motivated initiatives based on flimsy evidence), in recent years there has been an astonishing growth in scholarly output about and around the economics of nudge. And now, while the hybrid field continues to flourish, Routledge announces a new four-volume collection to provide users with a much-needed compendium of foundational and the very best cutting-edge scholarship. The collection is co-edited by Cass R. Sunstein (Robert Walmsley University Professor at Harvard), the co-author (with Richard Thaler) of the pioneering Nudge: Improving Decisions About Health, Wealth, and Happiness (2008), and Lucia Reisch of the Copenhagen Business School. The Economics of Nudge is fully indexed and has a comprehensive introduction, newly written by the editors, which places the collected material in its historical and intellectual context. It is an essential work of reference and is destined to be valued by scholars, students, and policymakers as a vital resource.