http://blog.world-mysteries.com/science/the-forbidden-book-of-enoch
Whether or not someone believes whats written in any particular book, there are unusually some interesting clues that can be discovered.
http://blog.world-mysteries.com/science/high-technology-in-the-bible
http://blog.world-mysteries.com/category/ancient-writings/religious-texts
http://listverse.com/2013/10/04/10-forgotten-ancient-religions
http://www.alternet.org/belief/20-weirdest-religious-beliefs
http://www.toptenz.net/top-10-mysterious-texts.php
Over the decades & centuries, several puzzling & mysterious things have been written.
http://www.sacred-texts.com/books.htm