The best definition for this website is to call it YouTube for documents. It has all kinds of documents covering hundreds of topics. Search for the ones you want and download or share them with others.
2- Free eBooks
This website offers unlimited reading for all kinds of work be it fiction, romance, literature and non fiction. It requires a registration.
3- Many Books
This one here provides more than 29.000 eBooks for Kindle, Nook, iPad and most other readers. It includes some of the most popular titles, recommendations and recent book reviews.
This is one of the preeminent Internet publisher of literature, reference and verse providing students, researchers and the intellectually curious with unlimited access to books and information the web for free.
5- Flat World Knowledge
This is one of the world's largest and open college textbooks.
6- eBooks Directory
This is a daily growing list of freely downloadable ebooks, docs and lecture notes from all over the net.
7- Open Culture
This is famous ebook providing platform. It has more than 300 free ebooks to download.
8- Open Library
This one is a must see for teachers. It is the world's classic literature at your fingertips with over 100 000 free ebook titles.
9- Project Gutenberg
This one offers over 39 000 free ebooks: choose among free kindle books, download them or read them online.