As I noted in the preceding chapter, nearly half of the states in the United States have some process by which curricular materials, usually textbooks, are evaluated and endorsed at a state level. Publishers differentiate between two kinds of states. In what is called “open territory”—most of the East, Midwest, and Far West— publishers sell directly to school districts or individual schools. In “closed territory”—mostly in the South and Southwest—centralized adoption policies prevail. 1 Individual districts in the “closed territory” can usually buy nearly any book, but state funds can only be used to purchase approved texts. Of all the states in the “closed territory,” Texas and California (and now increasingly perhaps Florida) have the most power over what counts as official knowledge.