Book excerpt: From the late sixteenth century until their expulsion in 1767, the Society of Jesus (Jesuits) played a pivotal role in the life of Spanish America. They educated the urban population, tended to the spiritual needs of city folk, conducted “popular missions” to correct doctrinal issues with the urban and rural populations, and administered missions among the indigenous populations on the frontiers. Jesuit missions stretched from northern Mexico to Patagonia in South America, and left a considerable historical and architectural heritage and patrimony. This volume outlines the historical development of Jesuit missions located in northern Mexico and South America, and illustrates the architectural heritage they left behind.