Over the next few decades, global migration is likely to play an influential role in shaping the nature of politics and economies internationally. This timely study illuminates possible implications of migrant flows from a development perspective. The authors survey the magnitude of the poor to rich-country flows, the rich-country policies that are driving them, and the multiple channels through which skilled migration affects development. They provide a rich discussion of the policy options, as they search for those that avoid the worst losses to poor countries while maintaining the most liberal feasible international migration regime.