The global migration potential in the world towards thehigher developed areas has been estimated to be about 80to 100 million people. Most of them would like to movepermanently. It is expected that the numbers will furthergrow in the medium-term future. Normally, the issue ofmigrationis linked to the issue of economic development. Economists, demographers andsociologists, among othersocial scientists have made only limitated effortstounderstand the causes and consequences of migration and toprovide the basis for an appropriate policy-making. The book collects eight contributions to the relevant issuesinvolved: Migration in a rational framework of decisionmaking; the performance of migrants; how they affect thesending countries; rural-urban migration in developingcountries. The options for migration policy are alsoconsidered. The book discusses newmethods to model theseproblems, provides new empirical findings and gives policyrecommendations. It should be of value to economists, demographers and sociologists.