The Book of Thoth by Crowley (take a deep breath)
The Book of the Law by Crowley (take two
deep breaths and keep the aspirin handy)
The Qabalistic Tarot by Robert Wang (correlates the Thoth, the TdM, the RWS and the Wang/Regardie Golden Dawn decks in one volume)
I have both of the Banzhaf Thoth books; Keywords I find useful, The Crowley Tarot less so.
I don't really have any use for Ziegler's Mirror of the Soul, and Arrien's much-panned work I've stayed away from.
Raven's tarot website (www.corax.com/tarot
) has basic card-by-card information on the Thoth that I always found reliable but brief. The site is harder to navigate now than it used to be (you have to click the suits on the Card Meanings page and then use the drop-down at the left side to get to individual cards).
Paul Hughes-Barlow's supertarot website has much more complete stuff.