ABSTRACT
Foreigners who enter, reside, or work in a country unlawfully are usually referred to as illegal, irregular or undocumented immigrants. The number of such persons residing in the industrial countries, as well as in some of the rapidly growing developing countries, has increased significantly over the last couple of decades. This phenomenon reflects a growing imbalance between the supply of migrants and the limited scope for legal immigration in the relatively prosperous economies. It also reflects the persistent demand for both documented and undocumented foreign labor in the advanced countries.
