For centuries, economics was dominated by the idea that we are rational individuals who optimize our own “utility.” Then, in the 1970s, psychologists demonstrated that the reality is a lot messier. We don’t really know what our utility is, and we care about people other than ourselves. We are susceptible to external nudges. And far from being perfectly rational, we are prone to “cognitive biases” with complex effects on decision-making, such as forgetting to prepare for retirement. In this book, David Orrell explores the findings from psychology and neuroscience that are shaking up economics—and that are being exploited by policy-makers and marketers alike to shape everything from how we shop for food to how we tackle societal happiness or climate change. Finally, he asks whether behavioural economics is a scientific revolution or just a scientific form of marketing.