Why have ninety million workers around the globe left their homes for employment in other countries? What can be done to ensure that international labour migration is a force for global betterment? This groundbreaking book presents the most comprehensive analysis of the causes and effects of labour migration available, and it recommends sensible, sustainable migration policies that are fair to migrants and to the countries that open their doors to them. The authors survey recent trends in international migration for employment and demonstrate that the flow of authorised and illegal workers over borders presents a formidable challenge in countries and regions throughout the world. They note that not all migration is from undeveloped to developed countries and discuss the murky relations between immigration policies and politics. The book concludes with specific recommendations for justly managing the world's growing migrant workforce.