For the serious, wealthy, and intelligent occultist, it is possible to get your hands on original ancient manuscripts. Currently the imposters and illusions of devils is on sale at ebay
You can also find several other rare occult tomes at http://www.wierus.com/ .
” Wierus was first created in France in the 90s as an association aimed at making an exhaustive bibliography of all known books and manuscripts related to the occult sciences / hermetism , and to have the rarest treatises scanned.”
“This project was made possible by a big family collection of printed and manuscript material we are caring of. Our library is quite large and covers most subjects from Alchemy, Magic, Inquisition, Demonology, Divination, with some exotic items from Middle East magical grimoires, to East Asian manuscripts from Tibet secret practices.”