Mexico was second only to the United States as the world's largest oil producer in the years following the Mexican Revolution. As the revolutionary government became institutionalized, it sought to assure its control of Mexico's oil resources through the Constitution of 1917, which returned subsoil rights to the nation. This comprehensive study explores the resulting struggle between oil producers, many of which were U.S. companies, and the Mexican government. Linda Hall goes beyond the diplomacy to look at the direct impact of a powerful, highly profitable foreign-controlled industry on a government and a nation trying to recover from a major civil war. She draws on extensive research in Mexican archives, including both government sources and the private papers of Presidents Alvaro Obregón and Plutarco Elías Calles, as well as U.S. government and private sources. Since the North American Free Trade Agreement has expanded United States business ties to Mexico, this study of a crucial moment in U.S.-Mexican business relations will be of interest to a wide audience in business, diplomatic, and political history.