- Directory of Open Access Books (DOAB)
From the OAPEN Foundation based at the National Library in The Hague. Database contains more than 5,000 academic, peer-reviewed books from 163 publishers. Note: Many of these are in other languages
Free medical books on the Internet.
- Great Books Online
Internet publisher of literature, reference and verse providing students, researchers and the intellectually curious with unlimited access to books and information on the web, free of charge.
- Internet Archive
Offers over 12,000,000 freely downloadable books and texts. There is also a collection of 550,000 modern eBooks that may be borrowed by anyone with a free archive.org account.
- National Academies Press Free eBooks
Created by the National Academy of Sciences to publish the reports of the National Academies of Sciences, Engineering and Medicine with more than 8,500 titles in PDF format.
- NCBI Bookshelf
Provides free online access to books and documents in life science and healthcare.
- OAPEN Library
Open Access Publishing in European Networks (OAPEN) Library contains freely accessible academic books, mainly in the area of humanities and social sciences.
- Online Books Page
Over 30,00 classic and out-of-copyright titles.
- Open Book Publishers
Founded in 2008 by a small group of academics at the University of Cambridge, Open Book Publishers publishes monographs and textbooks in the Humanities and Social Sciences. All books are available to read for free online.
- Open Library
Open, editable library catalog, building towards a web page for every book ever published. Open Library is a project of the non-profit Internet Archive.
- Project Gutenberg
One of the first producers of free online books. Contains thousands of classic works.
- World Digital Library
Project of the U.S. Library of Congress and UNESCO. Makes available on the Internet, free of charge and in multilingual format, significant primary materials from all countries and cultures.