If you are looking to market it then go with something in another language that is a cognate of English so that readers can make out what it means, but it still looks appealing on the cover. If you are doing it for yourself then call it something inconspicuous since a book of spells should be your most protected item.
"Black Arts and Incantations"
There used to be a troll in the Religion &Spirituality section who accused atheists of having a "book of pages." He was a troll, but I thought the book name was good.
the book of mormon