There are more international migrants today than ever before, and their number is certain to increase for the foreseeable future. Almost every country on earth is, and will continue, to be affected. Migration is inextricably linked with other important global issues, including development, poverty and human rights. Migrants are often the most entrepreneurial and dynamic members of society; historically migration has underpinned economic growth and nation-building and enriched cultures. Migration also presents significant challenges: Some migrants are exploited and their human rights abused; integration in destination countries can be difficult; and migration can deprive origin countries of important skills. For all these reasons and more, migration matters.