Agrarian reforms transformed the Mexican countryside in the late twentieth century but without, in many cases, altering fundamental power relationships. This study of the Tehuacán Valley in the state of Puebla highlights different strategies to manipulate the local implementation of federal government programs. With their very differing successes in the struggle to regain and maintain control of land and water rights, these strategies raise important questions about the meaning of the phrase "locally controlled development." Because Mexico is dependent on irrigation for 45 percent of its cash crop production, national policy has focused on developing vast government controlled and financed irrigation systems. In the Tehuacán Valley, however, the inhabitants have developed a complex irrigation system without government aid or supervision. Yet, in contrast to most parts of Mexico, water rights can be bought and sold as a commodity, leading to accumulation, stratification, and emergence of a regional elite whose power is based on ownership of land and water. The analysis provides an important contribution to the understanding of local control. The findings of this study will be important to a wide audience involved in the study of irrigation, local agricultural systems, and the interplay between local power structures and the national government in developing countries. The book also presents unique material on gravity-fed, horizontal wells, known as qanat in the Middle East, which had been unknown in the literature on Latin America before this book.