The Rider-Waite-Smith deck (1909)

The most successful transmission vector in the history of Western esotericism, and it does not look like a book.

Designed by A. E. Waite, drawn by Pamela Colman Smith, published by Rider in 1909. Its innovation was to give the minor arcana full illustrated scenes rather than arrangements of pips, which made the deck readable at sight — and it carries, invisibly, the Golden Dawn's Kabbalistic frame: the path attributions, the sephirotic correspondences, and the two pillars standing behind the High Priestess with B and J on them.

More people have met the sephirot through this deck than through every Jewish source in history combined. It is called Rider-Waite almost everywhere; this app calls it Rider-Waite-Smith, because Smith drew it and was paid once.