Open Textbook LibraryMaintained by the Open Education Network, textbooks distributed through this site feature reviews from faculty that have used the materials in their courses. Reviewers are confirmed to be working at their institution. All textbooks in this library are complete and openly licensed. Open textbooks are licensed so teachers and students can freely download, use, adapt, print and distribute the material. Sponsored by the University of Minnesota, Purdue University, and other leading institutions.