This is a wide-ranging book that discusses the challenges of applying behavioural science to developing public policy. Sunstein discusses the underlying philosophy and ethical challenges of when and how it is appropriate to intervene in people’s lives.

Using a wide-range of issues from leading a healthy life to saving the planet, the author steers a clear path through the topic, always coming back to the importance of free-will. He draws an important distinction between nudges that are educative (i.e., helping people be more informed) and those that change the ‘architecture’ (structure) of choices.

While we should always focus on improving people’s welfare, it’s always good to ask whether they would make the same choice if they were better informed and making an active choice. This book is worth reading for anyone involved in applying psychology to policy development.