Textbooks play a central role in the US education system. High school level World Geography textbooks are an important tool in the campaign to reform geography education in the United States, particularly through the introduction of the National Geography Standards. The status of the Standards in US schools is appraised. Five factors (authority, power, prescriptiveness, consistency, and internal issues) influence the adoption of education reform efforts like the Standards. These factors can be used to assess implementation. The textbook selection process is described and previous research in tracking implementation of the Standards in geography textbooks is presented. A preliminary analysis of four high school World Geography textbooks is conducted to measure change over time. (Contains 3 tables and 2 notes.)