World on the Move opens by describing the basic patterns and processes of migration and discussing the evidence used to measure migration, displacement, and their impacts. Subsequent chapters trace major population movements through human history, review the different reasons that propel the movement of human populations, and illustrate the many ways that migration affects us all. The final section focuses on international and national policies on immigration and displacement, including perspectives on birthright citizenship, migrant mothers and their children, and migration driven by climate change.