This edition of the Development Centre's annual report on policy coherence focuses on migration. The book examines the costs and benefits of migration for developing countries and how these flows can be better organised to yield greater benefits for all parties concerned -- migrant-sending countries, migrant-receiving countries, and the migrants themselves. It takes stock of what we know about the effects of migration on development, and distills from that knowledge a set of policy recommendations for sending and receiving countries alike. It draws on a large number of country and regional case studies co-ordinated by the OECD Development Centre to illustrate the mechanisms that link migration and development: labour-market effects, brain drain, remittances, diaspora networks and return migration.