So I got the book last night. Read through a few chapters. Definitely worth the $$ if you can swing it. If you're a fan of humates, charcoal, drainage layers, or "natural" fertilizers, Superthrive (not surprising) among other things, you're not going to be happy.
The book, which DEFINITELY NOT for beginners, is worth the money not for the mostly bad photos of Walter Pall's trees in the back of it, but for the horticultural science applied to bonsai in the text. The photos are not even really part of the book. They're just kind of jammed in the back as an afterthought.
There are 500 "myths/busted facts" in the book broken into chapters on things like soil, roots, fertilizers and size stuff. The info is broken up into short paragraphs, backed by horticultural studies and the most recent research, like how calcined clay is mostly better than Akadama. The book says there is no real reason to be importing Japanese dirt to the U.S., BTW. It just doesn't offer any advantages. Also, for those inclined to include more than three ingredients in soil mixes, you're not doing yourself any favors.
It goes on for over 100 pages of stuff. Some useful, some extremely esoteric or brain fogging, but it's interesting reading and reference....And BTW, the info on myc apparently came right out of one of my "quit wasting your money on it. It will show up on its own" only backed by research...;-)