International migrations have reached peculiar dimensions in current times of globalization of markets and innovations in information technology, communication and transport. Scholars of the theme come to suggest that we live in the era of migration, synthesized in five fundamental characteristics: globalization, acceleration, differentiation, feminization and recently politicization of migration. The Critical Dictionary of International Migrations presents the concepts derived from the theoretical debates on international migrations and also from the related areas that are suitable for migratory studies. This multidisciplinary and broad mix is the way to respond to the challenge of achieving approaches and concepts that offer measures, elements that facilitate the migration phenomenon and the different forms of mobility.