Library of Congress: The extensive digitized collections held by the Library of Congress are freely available, and include building surveys, newspapers, music, and photographs. www.loc.gov/collections/
Internet Archive: A non-profit all-digital library that offers free access to books, movies, software, music, websites, and more. archive.org/
Project Gutenberg: A library of over 60,000 free eBooks, with focus on older works for which U.S. copyright has expired. www.gutenberg.org/
Digital Public Library of America: Over 44 million images, texts, videos, and sounds from across the United States, including eBooks, primary source sets, and online exhibitions. dp.la/
Open Textbook Library: Nearly 1000 textbooks, all free to use and distribute, and licensed to be freely adapted or changed with proper attribution. open.umn.edu/opentextbooks/
HathiTrust (Global Public Domain only): A partnership of academic and research institutions, offering a collection of millions of titles digitized from libraries around the world. Search and access fully viewable materials and download materials where there are no third-party restrictions. www.hathitrust.org/
