In past years considerable interest has been focused on migration as an important cause of change in the genetic and demographic structure of human populations. This book synthesises the biological consequences of changes environments on the migrants and the genetic impact of immigration on the host populations. Patterns of migration, past and present and genetic, epidemological and demographic consequences are considered, forming a unique synthesis for human biologists in general. Individual chapters deal with the peopling of the continents, migration in the recent past, the effects of gene flow and rural to urban migration. In addition, a detailed analysis of the relationship between migration, adaptation and disease is presented. Advanced students and research workers in a wide variety of disciplines, including population genetics, demography, anthropology and social geography will find this book particularly valuable in relating their own special interests to other biological aspects of human migration.