- Books | Global Text Project.
- CK-12.org: Open textbooks on chemistry, biology, mathematics, etc.
- Connexions – Sharing Knowledge and Building Communities.
- Flat World Knowledge.
- Free Books from Samizdat Press
- Free Copyrighted Textbooks Community College Consortium for Open Educational Resources.
- Free Online Medical Textbooks: Textbooks on medicine
- Free Programming and Computer Science Books: Texts about computer and programming sciences
- freetextbookproject – The Free Textbook Project
- Free Textbooks – WikiEducator
- Introduction to Economic Analysis
- MedicalStudent.com: A digital library of authoritative medical information for all students of medicine.
- Online economics textbooks
- Online texts
- opentextbooks/lists – Open Knowledge Foundation Wiki
- Online texts: Collection of textbooks on mathematics
- Open Textbooks: Community College Consortium for Open Educational Resources
- OpenMathText.org
- Open Text Book
- Personal Collection Detail View
- Science Books Online.
- Science and Math textbooks
- Textbooks
- Textbooks – Download free ebooks.
- Textbooksfre.org
- Textbook Media: Free texts with ads.
- Textbooks | OER Commons.
- Textbook Revolt: Textbook exchange.
- Textbook Revolution
- Welcome to GTP – Global Text
- Welcome to Physics for Free.
- Wikibooks, collection of open-content textbooks.