Illegal immigration is a problem to not only a labor importing country but also to a labor exporting country, since the implementation of strict immigration policies, i.e., border patrol and employer sanctions, affects both economies. The purpose of this book is to complement previous studies on deportable aliens. The effects of such enforcement policies on the income or welfare of the foreign (labor exporting) country, the home (labor importing) country, and the combined (global) income of the two countries are examined.