In Mexico's Sierra Norte de Puebla, beliefs that were held before the coming of Europeans continue to guide the lives of modern Aztecs. For residents of San Mart n Zinacapan, life in and on the earth is animated by the same forces, through which people seek to maintain a cohesive view of the relationship of mankind, the cosmos, and the natural world. This delicate balance of the human spirit maintains the health and well-being of villagers,...