This publication presents the current situation with regard to the magnitude and economic impact of migrants’ remittances to their countries of origin. In 2004, remittances exceeded official development aid in several emigration countries: they totalled USD 126 billion according to IMF estimates. The book surveys the channels used to collect these funds; the role of banking systems and other financial institutions; the introduction of new technologies and their impact on fund collection; how the funds are transferred; and how to reduce the costs. Focus is also placed on the different ways in which migrants themselves participate -- together with non-governmental organisations, host countries and sending countries -- to open up new avenues for policies on development aid and co-development. The direct role that migrants can play at the local level is highlighted. Several countries and regions are illustrated: Southern European countries, Mexico, Turkey, North African and sub-Saharan African countries, the Philippines and some Latin American countries.