This is the third volume in the Gila River Indian Communityas Anthropological Research Papers series. As in the second volume, this volume presents new observations on the archaeology of the middle Gila River valley based on a full-coverage survey of 146,000 acres for the Pima-Maricopa Irrigation Project, sponsored by the U.S. Bureau of Reclamation, Department of the Interior, and administered by the Tribe under the Tribal Self-Governance Act of 1994. This study identifies a new approach for studying sites that contain protohistoric assemblages (AD 1450 to 1700). E. Christian Wells reviews the evidence for protohistoric settlement in central Arizona, introduces quantitative measures to identify pottery assemblages, and suggests potential avenues for future research.