The Pictorial Key to the Tarot, by A.E. Waite, ill. by Pamela Colman Smith [1911], at sacred-texts.com
There has been no attempt in the previous tabulation to present the symbolism in what is called the three worlds--that of Divinity, of the Macrocosm and the Microcosm. A large volume would be required for developments of this kind. I have taken the cards on the high plane of their more direct significance to man, who--in material life--is on the quest of eternal things. The compiler of the Manual of Cartomancy has treated them under three headings: the World of Human Prudence, which does not differ from divination on its more serious side; the World of Conformity, being the life of religious devotion; and the World of Attainment, which is that of "the soul's progress towards the term of its research." He gives also a triple process of consultation, according to these divisions, to which the reader is referred. I have no such process to offer, as I think that more may be gained by individual reflection on each of the Trumps Major. I have also not adopted the prevailing attribution of the cards to the Hebrew alphabet--firstly, because it would serve no purpose in an elementary handbook; secondly, because nearly every attribution is wrong. Finally, I have not attempted to rectify the position of the cards in their relation to one another; the Zero therefore appears after No. 20, but I have taken care not to number the World or Universe otherwise than as 21. Wherever it ought to be put, the Zero is an unnumbered card.
In conclusion as to this part, I will give these further indications regarding the Fool, which is the most speaking of all the symbols. He signifies the journey outward, the state of the first emanation, the graces and passivity of the spirit. His wallet is inscribed with dim signs, to shew that many sub-conscious memories are stored up in the soul.