I bought these cards three of four years ago, the first deck I bought for myself (my first deck was a gift). I was attracted to the pictures on the box, and bought them on a whim. When I opened them up, they really didn't speak to me. Try as I might, I couldn't do a reading with them at all. So I bought another deck and used it exclusively until a few months ago. I was beginning to have "issues" with this other deck, so I pulled out the Old Path and began using them in a professional readers course I was taking. After about 4 weeks, I suddenly found myself doing much better with the deck, but the additional images in the background of many cards had all of us in the class doing symbolism research in our spare time. For example, the toad in the tower card. For frogs there of course is the amphibian aspect, and the "touch a frog get warts" tale, as well as the "kiss a frog find a prince"... but what about a TOAD? Another difficult card for many of us was the 6 of swords, the single card in the deck with no human in it. We all knew what the 6 of swords meant, but what about this picture? Then serendipity struck again and I saw the book and found I had just enough cash to buy it. Another reviewer has mentioned that the book analyzes the cards to nth degree, and I agree. But for myself, and the other experienced readers in the class, it was a moment of "Eureka!" to find that the mushrooms in the page of pentacles hands added depth to the card, etc. And now, everyone in the class has gone out and bought the deck, including the facilitator.
SO, if you like the deck but aren't a walking encyclopedia of symbolic knowledge, the book is an excellent reference that will add depth to readings done with this beautiful deck.
The Tarot of the Old Path deck is beautiful and quite original, but all you need to interpret it is the instruction booklet included with the deck. The book doesn't add much except the meanings of the flowers pictured on the cards--which is less interesting than you'd think.