International migration has become a major domestic political issue in many countries and a major topic of international debate. Thus far, most of the attention has centered on the plight of refugees or on ways to curb the flow of illegal immigrants. As more and more migrants cross interstate boundaries, however, governments are realizing that immigration and asylum problems cannot be separated from broader socio-economic and political issues; nor can they be resolved by countries acting unilaterally. Even with this understanding, attempts to develop multilateral strategies to ease international tensions arising from uncontrolled migration will be complicated by economic disparities, regional political tensions, and mounting population and ecological pressures.Internal migration, particularly in terms of forced resettlement and urbanization, also gives rise to a myriad of problems relating to aspects of security. The increase in other major population movements, such as tourism and business travel, also has implications for security. Until recently, the question what is security? was rarely asked in the context of these developments. This was because there was a perceived consensus on what the nature of security was. The nature of security was held to mean national, political, and military security. Thus security was virtually synonymous with defense. The theoretical claim of this volume is that these developments are necessitating a redefinition of security. This volume provides major theoretical analyses of these trends as well as in-depth case studies that explore specific developments of major concern to scholars and other researchers involved with international relations, migration, and development issues.