Internet Libraries
Awesome Library: Organizes the Web with 37,000 carefully reviewed resources.
Bookshare: Free for Students With Dyslexia, Blindness, Cerebral Palsy, & Other Qualifying Disabilities. Access Over 800,000 Accessible E-books.
Digital Public Library of America: Discover 44,396,968 images, texts, videos, and sounds from across the United States.
Europeana: With a focus on fine arts and history, europeana boasts books, objects, records and recordings from across the European Union.
Internet Archive: Free online library: borrow modern books Download public domain books. Millions available.
onlinebooks.library.upenn.edu: Includes more than 2 million works in various formats.
Open Library: Millions of books available through controlled digital lending.
Project Gutenberg: Library of over 60,000 free eBooks.
publiclibraries.com - National Libraries: Directory of national libraries around the world.
publiclibraries.com - State Public Libraries: Directory of US state libraries.
thefreelibrary.com: Free Online Library.
Smithsonian Libraries: Most books available here are in the Public Domain unless otherwise noted, and are therefore free to download, use, re-use, and re-mix.
The Library of Congress: The Library of Congress is the largest library in the world, with millions of books, recordings, photographs, newspapers, maps and manuscripts in its collections.
The World Wide Web Virtual Library
Wiley Online Library: This digital library offers over 22,000 online books, 1,600 journals, and hundreds of reference works.
World Digital Library: Selection of rare books, manuscripts, and other materials dating back to 8,000 BC. The collection includes more than 19,000 publications from over 190 countries.

Local Public Libraries
Be sure to sign up and get a library card at your local library. You can use it to access your local library online and your state library network.  You can do a Google search for: libraries near me.  Ask your local library for details.

College and University Libraries
All colleges and universities offer free a online library to their students. Check with your physical library for details.