Hey Uwe,
All "bests" aside, I'm going to echo almost all of JMD's (apparently we have very similar bookshelves).
Bob Place's new book,
Tarot: History, Symbol, Divination, as a tight, intelligent history, a solid theory about the ideological underpinnings, a terrific look at the way TdM evolved into GD-based decks, and even a handy overview of divinatory usage.
Robert O'Neill's
Tarot Symbolism for open ended rumination on theoretical possibilities and an infectious love of history that spills over into every deck.
Dummett's
A Wicked Pack of Cards, which is the de facto source of most Tarot authors wanting to include researched history in their writing on the topic. Ferociously clear-sighted.
(edited to add: I almost forgot!
) Huson's
Mystical Origins of the Tarot, although I don't fully buy his origin theory, has superb history, and may be the only book in English to
reallycover the Decans, and the historical associations of the court cards. Equally invaluable are his compiled interpretations of meanings for all the cards from cornerstone Tarot authors: de Gebelin, Etteilla, Levi, Christian, Mathers, GD, Waite.
DuQuette's
Understanding Aleister Crowley's Thoth Tarot is one of the best books on any Book T derived deck. Hilarious and practical.
Meditations on the Tarot for a genuinely mystical look at the Trumps that reveals more and more each time you return to it.
Other faves for various moments and uses include Crowley's
Book of Thoth (though not for all people), Wang's
Qabalistic Tarot, Mary Greer's
Tarot Reversals,
Tarot Tells the Tale, Tarotbear's
It's All in the Cards as a keyword guide rec for WS beginners.
(n.b. I just bought Payne-Towler's book, and very much look forward to it, so in a few weeks I may be adding it to my list of must-haves.)