Crowley wrote a book on the use of it entitled The Book of Thoth.
Crowley made several distinct changes that make this deck different from most others. Most notably, he moved the trump card Strength from number 8 to number 11 and renamed it Lust.
It is a highly popular deck second only to the Rider-Waite-Smith one and especially famous with supposedly more advanced Tarot readers.
The painting style is very stark, and powerful symbolism is used throughout.