Anthropologists generally agree that an earthlodge is a dome-shaped, semi-subterranean structure constructed of tree and sapling walls plastered over with clay and supported by one or more large wooden posts. The entire dome is covered with earth, except for a central hole for ventilation and release of smoke from hearth fires. Resembling a mound from the outside, an earthlodge has one or more very low and narrow entranceways. These massive structures - the mid-continent's largest and most complex artifacts - are thought to have been used primarily for ceremonial or political gatherings because of the degree of labor involved in their construction, their size, and the scarcity of domestic goods found when they are excavated. This collection of papers provides a comprehensive gathering of the current research into earthlodges in a variety of Plains Indian cultures - Mandan, Hidatsa, Cheyenne, Oglala Sioux - in the territory of the upper Missouri River and its tributaries. Aspects of earthlodges ranging from their construction, architecture, maintenance, deterioration, and lifespan to the ritual practices performed in them; their associations with craft traditions, medicine lodges, and the Sun Dance; their gender symbolism; and their geophysical signatures are all discussed by acknowledged experts in the field. As technological advances allow an ever greater recognition of archaeological evidence in situ, the study of earthlodges will yield even more information on the peoples who built and used them. This volume provides a much-needed baseline for future earthlodge research as well as comparative data for the occurrence of earthlodges in other sections of North America.