The migration between Mexico and the United States is the largest emigration of people between two states in modern history. Today, thirty-six million Mexican Americans call the United States home. The Bracero period and recent Mexican migration have been well explored, but little is known about how mass migration arose in the first half of the twentieth century.Between Here and There is the first book to investigate the creation of modern US-Mexico migration patterns narrated from multiple sites on the borders and interior states. It illustrates how large-scale migration became entrenched in the socioeconomic fabric of both nations, drawing on the largest cohort study of Mexican migration during these decades. Through an analysis of the interplay between the US and Mexican governments, civic organizations, and migrants on both sides of the border, it offers a revisionist and comprehensive view of Mexican migration as a socio-economic system that reached from the Texas borderlands to California, as well as to Midwestern farming and industrial areas. Reacting to the political and economic events of these decades, migrant workers become increasingly assertive, even as migration becomes a major political issue in both societies. Those in Mexico claimed an expansive form of citizenship and land, while those in the United States joined efforts to claim New Deal rights, creating a base for later organizing. These dynamics shaped the establishment of the Bracero program that brought in more than four million workers and migration patterns that continue through the present day.