One of the key questions on international migration concerns its benefits and costs for the receiving economies. Assessing the overall net gain or loss to the economy from immigration is a challenging task both from a theoretical and an empirical point of view. Immigration can affect the receiving economy through several channels: wages or employment effects on native workers, changes in output structure, fiscal effects, effects on house prices, and so on. This book discusses the politics of international migration, as well as the policies and practices throughout the world.