The development, florescence, and subsequent demise of an organizationally complex cultural system in the American Bottom, part of the central Mississippi River valley, spanned a little over half a millennium. Cahokia, the largest Precolumbian site in the United States, is located within this segment of fertile floodplain, as are many other subsidiary settlements that varied greatly in terms of their size, internal structure, and occupational histories. Numerous projects over the past 30 years have resulted in the rapid accumulation of considerable information and divergent interpretations about the nature of the societies represented archaeologically by a series of superimposed settlement systems.