Ancient Puebloan communities thrived in the Mesa Verde region for centuries, and the abandonment of this area by Puebloan peoples remains an intriguing subject of archaeological research. Environmental change, resource depletion, and conflict are but a few of the proposed causes of the thirteenth-century emigration from the region. Clues to why the area was abandoned can be found in the many prehistoric villages scattered across the landscape. The Sand Canyon Archaeological Project was designed to examine ancient Puebloan communities northwest of Mesa Verde National Park in southwestern Colorado. In this innovative study, Varien and his colleagues examine thirteen sites from two residential communities in the Sand Canyon locality. Published in CD-ROM format, The Sand Canyon Archaeological Project: Site Testing presents a detailed chronological reconstruction of community settlement patterns, develops new methods for measuring the length and season of site occupation, and examines site-formation processes in an effort to better understand the details of individual site abandonment. It includes 124 color photographs, 188 maps and charts, and 195 tables, with hyperlink and search capabilities that allow the reader to easily navigate the text. This publication is an essential resource for archaeologists working in the Southwest and for anyone interested in the study of ancient communities and the phenomenon of abandonment. Mark D. Varien is Director of Research at the Crow Canyon Archaeological Center in Cortez, Colorado.