Open Textbooks

Open Textbooks are open educational resources (OER); they are instructional resources created and shared in ways so that more people have access to them.
That’s a different model than traditionally-copyrighted materials.
OER are defined as “teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others” (Hewlett Foundation).