Seibal is a major ruin of the southern Maya lowlands, its vast ceremonial center covering several high hills on the banks of the Pasion River in the Guatemalan Department of Peten. In five volumes published over a 15-year period, the archaeological team headed by Gordon R. Willey presents a comprehensive review of their fieldwork from 1964 to 1968 and the results of many years of subsequent data analysis. The volumes also report on explorations in the peripheral settlements outside of the Seibal center and provide a regional view of the evolution of lowland Maya culture from the Middle and Late Preclassic through the Late Classic periods.