The University of California Press has been creating an online collection of books since back in 1982 and a lot of that collection is available to the general public online.
The entire eBook library includes almost 2,000 books from academic presses on a range of topics, including art, science, history, music, religion, and fiction. While students and faculty can access this entire collection, the general public can read about 770 of those titles. There is even a way for readers to purchase print editions of these eBooks directly from the publishers.
AppNewser has more:
You can’t download the eBooks files, but they’re searchable and browse-able by chapters. To get started, use this special browsing page to access free books by categories. You can’t download the eBooks to your reader, but you can print from the site. If you use Calibre, you can save the .html version of the chapters and convert that to your chosen eBook format for non-browser reading. There’s also a bookbag option to bookmark your favorite titles so you can return to the site to read at a more convenient time.