This study is a reinterpretation of nineteenth century Mexican American history that examines Mexico's struggle to secure its northern border with repatriates from the United States in the aftermath of a war resulting in the loss of half its territory. Responding to past interpretations, Jose Angel Hernández suggests that these resettlement schemes centered on the developments of the frontier region, the modernization of the country with loyal Mexican American settlers, and blocking the tide of migrations to the United States to prevent the depopulation of its fractured northern border. Through an examination of Mexico's immigration and colonization policies as they developed throughout the nineteenth century, the book focuses primarily on the population of Mexican citizens who were “lost” after the end of the Mexican American War of 1846–1848 until the end of the century.