This issue of Archaeology Southwest reviews some of the big picture questions in Paleoindian research today: who were the first peoples to reach the Americas? When did they arrive? What was the relationship between the makers of Clovis spear points and the extinction of megafauna? Contributors focus on data recovered from sites in Arizona, New Mexico, Oklahoma, and Sonora. Many of these research programs are supported by endowments established by Joe and Ruth Cramer, whose philanthropy is changing the direction of Paleoindian research throughout North America.