Project Gutenberg is a volunteer effort to digitize and archive cultural works and encourage the creation and distribution of eBooks. The library includes over 60,000 free eBooks.
Related Tools
InfoBooks
InfoBooks features over 3,500 Books in PDF format belonging to the public domain. You will be able to access Creative Commons licensed materials prepared by students, universities, governments, and subject matter experts.
LibriVox
Librivox provides free audio books from the public domain. You will find 5000+ books in their catalogue.