Are natural assets a curse? In The Bottom Billion I argued why I thought they often did more harm than good to the poorest countries. But the real measure is not just the damage they cause, but their harm relative to their potential. Natural resources are the largest assets available to these societies. Their known natural capital has been estimated to be worth double their produced capital. The failure to harness natural capital is the single-most important missed opportunity in economic development. Since writing The Bottom Billion I have accumulated more research on the subject, as have many others. Indeed, whether an abundance of natural assets is a blessing or a curse is currently one of the disputes raging among economists. There are some high-visibility instances of natural assets appearing to ruin a country: Sierra Leone’s diamonds, for example, seemed to shred the fabric of that society to pieces; Nigeria’s oil fueled the corruption of the political class. But are these just outliers? After all, Botswana harnessed its diamonds to produce the fastest growing economy in the world, and Norway used its oil to achieve the world’s highest living standard. The question becomes whether there really is a “resource curse,” and whether, if it does exist, it is limited to countries with deeper problems. I have come to regard this as the most crucial issue in the struggle to transform the poorest societies. The revenues that they could get from natural assets are enormous, dwarfing any conceivable flows of aid. They could certainly be transformative. If they deliver, any efforts to inhibit the extraction of natural assets from the poorest countries are not simply counterproductive but irresponsible, impeding the path out of poverty. If, on the other hand, natural assets backfire, then there is an argument for leaving them in the ground. There would indeed be the basis for an alliance between the environmental lobby, pressing for natural assets to be conserved, and the development lobby, fighting to end mass poverty.