What are Open Educational Resources?
Open Educational Resources (OER) are teaching, learning, and research materials that are in the public domain or have been released under a copyright license that permits anyone to freely use them. OERs often also allow users to reuse, repurpose, adapt, and redistribute them. These resources will continue to be freely available to you after you graduate.
Open textbooks are helpful both for learning concepts for the first time and for reviewing and revisiting material you've previously learned.