The end of the Pleistocene era brought dramatic environmental changes to small bands of humans living in North America: changes that affected subsistence, mobility, demography, technology, and social relations. The transition they made from Paleoindian (Pleistocene) to Archaic (Early Holocene) societies represents the first major cultural shift that took place solely in the Americas. This event—which manifested in ways and at times much more varied than often supposed—set the stage for the...