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 than they were at the start of this century. Why have these places fallen behind? And what can we do about it? World-renowned development economist Paul Collier offers his candid diagnosis of why some regions and countries are failing, and a new vision for how they can catch up. He also shows how renewal is achievable through a combination of collective learning, moral leadership and local agency.