This study seeks to investigate the process of rural out-migration in Mexico, from the perspective of rural sending communities. The research deals with migratory behavior as both a dependent and independent variable. Migration as a dependent variable is being studied primarily in terms of the impact of specific government policies and programs and of certain rural community characteristics upon rates and patterns of out-migration (specifically, the average annual rate of community population change due to out-migration, selectivity of migrants leaving the community in terms of age, sex, education, occupational skills, and other characteristics, the ratio of temporary to permanent emigration, and migrants' choices of destination, all measured over the 1950-1975 period). Out-migrations and return migration are also being studied as independent variables affecting the social, economic and political life of rural communities. Data are being gathered on four principal populations: (1) current residents of the research communities who have never emigrated; (2) current residents of the communities who have returned after temporary migration (mostly to the United States); (3) former residents of the research communities now permanently established in principal cities within Mexico; and (4) former residents now permanently residing in the United States.