Speaking of collaborations, Decker and Michael Dummett have a new book published last month in Great Britain: The History of Occult Tarot. You can pre-order the book from
Amazon, since it will be out in another month in the United States, but if you absolutely can't wait, you can order it from the British
Amazon.com. There you'll find more about the stories behind the Knapp-Hall deck, as well as chapters on Crowley, Dion Fortune, and Eden Gray, among many others.
The book also contains photographs of the second tarot deck Waite was working on with another artist (not Pamela Colman Smith) which are quite fascinating and beautiful. The photograph and the top of the page shows Mary Greer looking at these images, as she, "Bunny" Bob O'Neill, and Ron Decker exchange pleasantries at the end of the lecture.