During the last few decades the world has experienced an unprecedented level of cross-border migration. While this has generated significant socio-economic gains for host countries, as well as sometimes for the countries of origin, the costs and benefits involved are unevenly distributed. Consequently, growing global population mobility is a hotly debated topic, both in the political arena and by the general public. Amidst a plethora of facts, opinions and emotions, the assessment of migration impacts must be grounded in a solid scientific evidence base. This analytical book outlines and applies a range of the scientific methods that are currently available in migration impact assessment (MIA). The book provides various North American and European case studies that quantify socio-economic consequences of migration for host societies and for immigrants themselves.