This is a very good book!
Given the Japanese martial arts background of the Author, it still remains very relevant to the martial arts instructor of any system or style. It has lots of background theory on learning approaches (including some on the scientifically questionable 'learning styles', which is handled very well nevertheless). The author is obviously a very capable, very experienced instructor and his wealth of experience really gets the reader into the meat of the subject matter.
I would have likes to see more specific examples of how the theory chapters link in with the teaching and structuring of the martial arts classes, but this is a fairly minor quibble and likely stems from wishing the author would have covered these kinds of things a bit less generically (and fully); I can't fault the book as a whole, however, and I would recommend this book without question to both instructors and students of the martial arts... If your instructor does things the way Mr Kane does things, then he is a very good instructor indeed. And if he doesn't... well, buy him the book!
Buy this book; at the price, you won't regret it.