In this interdisciplinary study of colonial San Francisco, Barbara L. Voss examines one of the most diverse population’s ethnogenesis - the passive and active creation of an ethnic group. Through archaeological analysis of religious, environmental, cultural, and political differences in the El Presidio region in California, Voss reveals the development of social identities with the colony. Voss attempts to reconcile material culture with historical records, challenging widely held beliefs about ethnic growth. Focusing on the colonizers rather than the colonized, Voss presents a theoretical framework that will guide archaeologists’ future investigations.