Migration promises to be one of the most pressing topics of debate in the twenty-first century. Emigrants are leaving from an ever increasing number of countries, and their destinations are equally varied, so that the phenomenon is, using a much abused word, global. The rapid decrease in transport costs, the availability of cheap information, the political and economic upheavals in eastern Europe, and the outbreak of local conflicts have all meant that the number of potential emigrants has multiplied. At the same time, many former countries of emigration have reached an overall standard of living that makes them potential destination areas.

Thus, one of the most difficult challenges of the twenty-first century will be how to manage immigration and emigration. Destination countries would like to control the inflow of foreigners, but their policies risk being ineffective because the flows are changing and becoming more complex as labor immigration is replaced or largely integrated by family reunification (about half of the foreigners in Europe entered as family members) and refugees. In addition, development policies designed to help countries of origin to raise their standard of living will take time to have any effect so that individuals' propensity to emigrate will not decrease in the near term. The political changes that are necessary in many countries of origin cannot be completed easily; consequently, the demand and supply of migrants will not be balanced in the near future.

The southern European countries are a very interesting case to study.