Left behind places can be found in prosperous countries-from South Yorkshire, integral to the industrial revolution and now England's poorest county, to Barranquilla, once Colombia's portal to the Caribbean and now struggling. More alarmingly, the poorest countries in the world are diverging further from the rest of humanity. Why have these places fallen further behind? And what can we do about it? World-renowned development economist Paul Collier has spent his life working in neglected communities. In this book he offers his candid diagnosis of why some regions and countries are falling further behind, and a new vision for how they can catch up. Collier lays the blame for widening inequality on stale economic orthodoxies that prioritize market forces and centralized bureaucracies like the UK Treasury. In contrast, a new wave of academic research has revealed the crucial role of collective learning, social capital and local agency in reversing decline and equalising life-chances. Drawing on insights from social psychology, moral philosophy and behavioural economics, as well as a range of illuminating case studies, Collier shares a galvanizing vision for a more inclusive, prosperous world.