Many decks published today are identified, in part, as being based on the Rider-Waite-Smith Tarot (RWS) or as not being based on it. That identification only means something if you know what the RWS Tarot is. For seasoned tarot enthusiasts, it is ingrained, but for people new to tarot, it might be helpful to understand the importance of the RWS Tarot and its characteristics.
Arthur E. Waite was the creator of the deck, although some question to what extent he was involved with the design of the cards, particularly the Minor Arcana. He was mystic and occultist and member of the Golden Dawn. He invented (although he claims it is ancient) the Celtic Cross Spread, one of the most well-known