During my research regarding origins of ancient knowledge I came upon a site that I found both interesting and fascinating. It is called The Internet Sacred Text Archive. Here is a short description:
Welcome to the largest freely available archive of online books about religion, mythology, folklore and the esoteric on the Internet. The site is dedicated to religious tolerance and scholarship, and has the largest readership of any similar site on the web.
They have a vast amount of literature there so you may want to bookmark it as it will take several visits to explore the site.
Tags: Sacred Text Archive