Open textbooks are textbooks that have been funded, published, and licensed to be freely used, adapted, and distributed. Many of 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.
The general repositories include textbooks as well as learning objects, practice exercises, instructional videos, modules, free interactive math and science simulations, course materials, lesson plans, multimedia, lectures, and more.
Using an OER search engine allows searching of multiple OER sources at once.