In "The Tarot," Case published the Hebrew letter attributions of the Golden Dawn for the first time. Also made public was the Tarot tableau, a pattern for laying out all of the Tarot Keys which reveals certain relationships and dissimilarities among them. This tableau was used by the American branch of the Hermetic Order of the Golden Dawn when Case was Praemonstrator of that Order. This was the first published book to reveal almost all of the Tarot attributions on the Qabalistic "Cube of Space" diagram. Of course the Sepher Yetzirah is the source of the link between the Cube of Space and the Hebrew letters.
Until the publication of this book, most English speaking occultists had never heard of the "Cube of Space" and were not aware how it related to the much better-known "Tree of Life" diagram. In fact, until the mid-1990's there were almost no other books in print which even mentioned the Cube of Space. The ones that do refer and defer to Case's pioneering and authoritative work on the subject.
B.O.T.A. repeatedly emphasizes that Tarot is primarily a tool for meditation, not fortune-telling. After explaining the B.O.T.A. method for Tarot divination in his book "The Tarot, A Key to the Wisdom of the Ages," Case specifically explains the differences between divination and fortune-telling.