Forgotten Books is an independent publishing company specialising in out of print books. They are putting over 1,000,000 books onto their website www.forgottenbooks.org at a rate of over 5000 per day. These are available as free ebooks (you can download 50 for free, then have to buy extra credits or become a member) and are also for sale in paper (aka "dead tree") form on Amazon.com or its sister sites in other countries such as amazon.co.uk or amazon.de. Libraries, schools and other eductional establishments can get a free membership with unlimited downloads at www.forgottenbooks.org/schoolsmembership.php .
The free ebooks and printed versions are all very high quality in my experience. Membership is buy buying extra credits as a 1 - off or by signing up for an "x downloads per month" style membership where longer-term commitments means you get more downloads for less money.
Forgotten Books’ catalogue contains books published over several
centuries and on every conceivable topic, from classics of fiction (both well
known and undiscovered) to scientific, religious and philosophical treatises. Many
of these books are of historical and educational value; for example the
earliest existing English language book: a cookbook entitled “The Forme of
Curry”, or Charles Darwin’s original “The Origin of Species”.
Forgotten Books was founded by David Forsythe in 2007. It has a facebook page at www.facebook.com/forgottenbooks .