If someone who has actually read "Arcana IV" had written a review, I would have made this a comment rather than a review. Since there are no reviews as yet, I thought I could perhaps at least provide a little help to people interested in this book. My son is a professional musician and composer and is, of course, absolutely brilliant! My son has long admired John Zorn and his music, owns Vol. I and Vol. II of this series and just requested III and IV for Christmas. As far as I'm concerned, this makes "Arcana IX" a highly recommended book.