There are also some reviews on the books section.
Basically though (and yes I dislike the book) is you had two Shodans spend about six months in Japan after which they wrote a book. Twigger of Angry White Pyjamas fame has more experience although he probably can't draw that well.
The kindest I heard about the philosophy section is that it is Toheiesque - I've heard worse.
Intermediate to advanced - I don't think so.
Best thing I can say it it is a beautiful coffee table book to keep Grandma happy when she asks what all those bruises on your forearm are all about.