International migration has reached new heights since the 1960s. Altogether, some 215 million people live in countries other than their countries of birth, and according to surveys, another 700 million say they would leave their homes and move to another country if they could. Nations-both sending and receiving-have responded to this growing international migrant flow with new laws and domestic programs. In receiving countries, they include laws and programs to control entry, encourage high-skilled immigration, develop refugee policy, and speed assimilation. In sending countries, governments...