Open educational resources can be defined as "textbooks [or other materials] that have been funded, published, and licensed to be freely used, adapted, and distributed." Typically open textbooks are available as a pdf, epub, or html files that are available at no cost to students and instructors. True open content is licensed so that it can be freely printed, distributed, and even adapted, with correct attribution. Vendors like Amazon and Lulu may be able to provide print copies of open texts, and they can be printed locally as well. (WSU Libraries, OER LibGuide)
Below are the repositories we recommend you use to start your search for OER textbooks and course materials.