At intervals since 1941 the Mexican Society of Anthropology has organized and conducted a series of round tables, each devoted to an important and current problem in Mexican archaeology or to the prehistory of a certain geographic area of Mexico. The eleventh Mesa Redonda was devoted to the Valley of Teotihuacán and its environs, and was held in México, D. F., between August 7 and 13, 1966. It consisted of numerous sessions dealing with anthropogeography, physical anthropology, archaeology, ethnohistory, and social anthropology. Meetings were held in the auditorium of the National Museum of Anthropology, where a special temporary exhibit on “Discoveries at Teotihuacán” was displayed, and on the final day of the conference an excursion went out to Teotihuacán. The participation of fifty specialists in a week of meetings emphasized the significance of the great archaeological zone of Teotihuacán, with its spectacular ceremonial center, and the widespread influence of the people and culture of Teotihuacán throughout Mesoamerica.

The five papers in this volume, all of them in Spanish, were presented in the session on anthropogeography, and hopefully will set the stage for papers from other sessions dealing more specifically with the ancient people of Teotihuacán and their cultural attainments and activities. The papers included in the volume are: “Present Day Climate of Teotihuacán,” by Enriqueta García; “Geology, the Nature and Development of the Valley of Teotihuacán,” by Federico Mooser; “Petrographic Study of the area of San Juan Teotihuacán, State of México,” by Alfredo Sotomayor Casteñeda; “Study of Bony Remains from Tepeapulco, Hidalgo,” by Ticul Álvarez; and a paper on climate and agriculture at Teotihuacán by José L. Lorenzo, who also edited all of the papers for this volume.

These are technical reports containing maps, charts, and diagrams as well as detailed texts meant to be used primarily by geographers and anthropologists in considering the total ecological situation of a small section in central Mexico. They are valued contributions to the geology, geography, and natural history of the Valley of Teotihuacán and its environs and will provide important basic data for future scholars investigating the city’s rise and fall.