The Book of Azathoth is an homage to the American sci-fi and horror author, H.P. Lovecraft. The 78 card deck is designed to give the feel of being of Lovecraft's universe, as used by one of his characters.
The deck is intended to be as the mad old wizard Whateley might have consulted prior to calling forth Yog-Sothoth, or perhaps the same as the ones Keziah Mason kept on the shelf alongside her flesh-bound copy of the Necronomicon.
The cards are bigger than usual (3-1/2" by 5"). The artwork is pen and ink on Bristol board.
Trump card titles (and order) are those of the RWS (except for The Magus), Suits are the same as RWS (Wands, Cups, Swords, Pentacles), Courts are a hybrid (King, Queen, Prince, Princess), Pips are titled after Thoth: Dominion, Virtue, etc.
For the most part, the attributions of Hebrew letters and astrological symbols on the Azathoth's Trumps are the same as those used in the Thoth, but there are a few exceptions. All of the minors on the Azathoth have printed Hebrew letters and astrological symbols.