This document discusses the high cost of textbooks and the potential for open educational resources (OER) to provide more affordable alternatives. It notes that the 5 major textbook publishers control nearly 90% of the market, limiting competition and driving up prices. As a result, many students opt not to purchase required textbooks or purchase older editions. The document then introduces OER, which are open-licensed educational materials that can be freely reused, revised, remixed, and redistributed. It provides examples of open educational websites and resources and encourages readers to adopt, adapt, and create OER when possible to increase access and affordability of educational content.