In this highly readable and personal account built on interviews with emigrants from many countries, Guest, business editor of The Economist, contends that voluntary emigration almost always benefits the emigrants and usually benefits their countries of origin and destination, too. In recent decades, Chinese and Indian overseas diasporas have played a crucial role in generating rapid growth in their home countries, as their members have created businesses and opened foreign marketing channels. To be sure, international migration also has a dark side, in the form of criminal organizations and terrorist networks that exploit open borders. But Guest argues that immigration is an especially important source of vitality for the United States, which does a remarkably good job of providing a hospitable and productive home for immigrants and their children, compared with other developed countries. In Guest’s judgment, this receptiveness will assure that the United States remains number one in the world economy -- unless thoughtlessly more restrictive immigration policies take hold.