Open Textbook Library
The library currently includes 697 textbooks, with more being added all the time. These books have been reviewed by faculty from a variety of colleges and universities to assess their quality. They can be downloaded for no cost, or printed at low cost. All textbooks are either used at multiple higher education institutions; or affiliated with an institution, scholarly society, or professional organization.
LibreTexts
An effort of the California state University system, the LibreTexts platform combines extensive textbook holdings with digital features such as integrated code-running widgets or example files. You can browse by subject or search by a topic.
Books & Journals
Project Gutenberg
Contains 59,000 free eBooks that you can download or reach online.