Paul Collier’s book The Bottom Billion shows what is happening to the poorest people in the world, and offers ideas for opening up opportunities to all. Paul Collier studies the political and economic problems of the very poorest countries: 50 societies, many in sub-Saharan Africa, that are stagnating or in decline, and taking a billion people down with them. His book The Bottom Billion identifies the four traps that keep such countries mired in poverty, and outlines ways to help them escape, with a mix of direct aid and external support for internal change. From 1998 to 2003, Collier was the director of the World Bank’s Development Research Group; he now directs the Centre for the Study of African Economies at Oxford, where he continues to advise policymakers. "Collier sheds much light on how the world should tackle its biggest moral challenge. [He] shows, too, how far western governments and other external actors are from currently giving the sort of help these countries desperately need."-Martin Wolf, Financial Times