I have been thinking about this question for a while, and find it difficult to actually pin-point particular books which are amongst my 'favourites' which I, in indirect ways, relate to Tarot. Of course, the Bible is one. Not only because of the historical connections between the two, but also because so much of it is so image-rich that much of Tarot may be therein reflected, especially, for myself at least, Genesis, the synoptic Gospels and the Apocalypse.
But if I had to list my favourite, it would probably be a book I have mentioned before in these Forums, namely Rudolf Steiner's Philosophy of Freedom. Therein numerous aspects come to mind. The development of various faculties, the inherent freedom one has, ethical considerations, and the role of the imaginative faculty in penetrating with understanding what is at hand.