Nudging is a subtle, but surprisingly controversial, technique for changing people's behaviours. This may seem like an unusual time to write a book about nudging. The formal practices of nudging have been around for over a decade (they have been informally present for much, much longer). “Nudge Units” and associated initiatives have been established in over a hundred states and nudges are an accepted part of the policy world. Despite being well established, the value of nudging is being challenged from various perspectives. Some question whether subtle nudges are up to the task of tackling the daunting global political, economic, socio-cultural and environmental challenges of our age (Pedwell 2022). Others have cast doubt on the scientific insights on which nudging is predicated. In these contexts, it is to be expected that readers may think one of two things (or maybe even two of two things): everything that needs to be said about nudging has already been articulated; and why write about something which may already be outdated?

We claim that while much has been written about the pros and cons of nudging there is significant uncertainty about its long-term prospects and direction of travel. In a recent review of nudging Ed Bradon made two interesting observations (Bradon 2022). First, he claimed that despite nudging's global spread, nudging-related practices are still relatively underutilized policy tools. Bradon estimates that an average-sized national government which mobilized nudging across all of its departments and policy regimes could be expected to deploy 6,000 nudges. He contrasts this to the 165 nudge trials that have so far been developed in two of the most prominent nudge units in the United States. Second, he claims that approximately 80 per cent of attempts to change people's behaviours, or reform organizational practices, fail. In this context Bradon argues, “Nudges are a valuable, modestly resourced and […] dramatically underused way of improving people's lives. Abandoning them now would be like discovering Aspirin then immediately shutting down production because it doesn't cure cancer” (2022).

This book is based upon the premise that we are still in the relatively early phases of the use and development of nudging, and that the future is likely to be characterized by significant innovation and change (some of it good, some of it not so good) in the use of this policy tool.