These books have been reviewed by faculty from a variety of colleges and universities to assess their quality. These books can be downloaded for no cost, or printed at low cost. All textbooks are either used at multiple higher education institutions; or affiliated with an institution, scholarly society, or professional organization.
Open Learn is an initiative of The Open University, UK. It provides supplemental materials for educators, including articles, podcasts, videos, games, and much more. In addition, it offers more than 700 free online classes.