'A pathbreaking book that for the first time brings smart policy insights into contact with creative, rigorous testing.This book sets the standard for all future scientific evaluations of "what works".'Donald P. Green, Columbia University, USA How can governments persuade citizens to act in socially beneficial ways? Thaler and Sunstein's book Nudge drew on work from behavioural economics to claim that citizens might be encouraged through 'light touch interventions' (i.e.nudges) to take action.This ground-breaking successor to Nudge is now available in paperback, with a new preface.In it, Peter John and his colleagues argue that an alternative approach to nudge also needs to be considered, based on what they call a 'think' strategy. Their core idea is that citizens should themselves deliberate and decide their own priorities as part of a process of civic and democratic renewal.The authors not only set out these divergent approaches in theory but they offer evidence from a series of experiments to show how using techniques from 'nudge' or 'think' repertoires work in practice and how that practice is made effective.