An ‘open’ textbook is a textbook created using an open copyright license, like Creative Commons, and shared with no or low cost at the point of use for students, teachers and members of the public“ https://insights.uksg.org/articles/10.1629/uksg.427/

Open textbooks are textbooks that have been funded, published, and licensed to be freely used, adapted, and distributed.

Like traditional textbooks, open textbooks:

• Are written by experts in the field
• Undergo a process of peer review
• Go through professional editing and development
• Publishers and authors are paid for, by the funding organization or grant, instead of relying on sales to pay back their investments

Open Textbooks: An Untapped Open Educational Resources For Librarians To Promote [Slides]