Two hundred years after Adam Smith wrote the Wealth of Nations, Gunnar Myrdal produced his seminal work on the Poverty of Nations. This is ironic for, in the intervening two centuries, the world shifted not from wealth to poverty but the other way round. The agriculture, industrial and scientific revolutions heralded unprecedented improvements in material well-being and social indicators. But the gains were so uneven that even as large parts of the world enjoyed remarkable prosperity, mass poverty continues to be a complex and compelling challenge in much of the Third World. Within the Third World itself there has been an extraordinary diversity of experience in reducing poverty with some remarkable successes and some dismal failures. This record of experience has expanded our understanding of the causes and consequences of poverty, but it has also thrown up more questions than answers. Why do some policies work and some don’t? Why do policies that work in a certain context or in a certain country not work in another? Why do the same policies produce dramatically different results in different settings and situations?That, I believe, would be an error.