Initiative through the state of Ohio's OhioLINK for Affordable Learning.

Large collection maintained by the Open Textbook Network. Contains verified peer reviews.

Open textbooks from Rice University.

British Columbia's open textbook collection.

List of textbooks approved by the AIM.

Open textbooks jointly developed by Terry College of Business of the University of Georgia and The Daniels College of Business of the University of Denver

Open-access publisher of science books and journals. Indexed in ISI Web of Science Book Citation Index.

Short list of mathematics textbooks from different content providers.

Saylor Academy's open textbooks.

Collection of textbooks and other teaching materials from leading institutions of higher learning.

The Directory of Open Access Books provides access to titles from a variety of different publishers.

The OAPEN library provides access to to peer reviewed academic books.

Open access titles from publisher Taylor & Francis.

Publisher of high-quality open access academic research in the Humanities and Social Sciences.

Searches multiple OER repositories at the same time.

Directory of books and textbooks published through the Pressbooks platform.

Federated search tool

The Directory of Open Access Books provides access to titles from a variety of different publishers.

Publisher of high-quality open access academic research in the Humanities and Social Sciences.

The OAPEN library provides access to to peer reviewed academic books.

Open access titles from publisher Taylor & Francis.

Publisher of high-quality open access academic research in the Humanities and Social Sciences.