Since the end of the 20th century, migrancy has vastly increased in frequency and volume. Today, one person out of thirty will have left the land where they were born, for reasons economic, political, or climate-related... Not a single place on earth remains unaffected by this phenomenon. These population movements have sparked off many debates in the receiving host countries. This clear, precise book summarizes of the history of migrancy and draws up a list of pertinent questions that so-called "developed" nations must answer today.