Open textbooks can be defined as "textbooks that have been funded, published, and licensed to be freely used, adapted, and distributed." Typically open textbooks are available as a pdf, epub, or set of html pages that are available at no cost to students and instructors.

True open textbooks are licensed so that they 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.