Goran Powell combines insight and authority born of years of experience with a down-to-earth and humorous style. I know there have been some reviews of this book by people who have themselves performed the Thirty Man Kumite - this is from the other end of the spectrum, from someone just a couple of years into that journey. The parts of the book I appreciated most were the reflections on how we learn - how periods of struggling with an idea, or drilling something without feeling comfortable with it, are interspersed with moments of enlightenment when it suddenly makes sense - and on the nature of fear.
Goran describes the fear he encountered at various points in his training, and explains how he accepted it and harnessed it as a positive force - with some interesting thoughts on how professional fighters have dealt with the same problem.
The book isn't just about the build-up to the ultimate challenge (after all, for most of his martial arts career he didn't know he would one day do the Thirty Man) but about all the challenges along the way, and that's something anyone can learn from whatever the specific nature of the challenges they face.