This book is designed for kids to learn kendo but it is useful for instructors as well. It includes brief introduction of Japan and Japanese culture that is related to kendo.
Since it is designed for kids, all the explanations are short and easy to understand, but to the point. So it is very useful for instructors who are inexperienced in instructing kendo.
It is very helpful for me, who is not a native English speaker, to learn vocabularies to explain kendo more easily and precisely.
I find some small mistakes. For example, when explaining three stances of kendo, it introduces chudan as jodan (p. 22).
However, since the author knows what he's talking about, I can say that it is an honest mistake. He should have checked it before publishing it.
Some explanations on kendo history can be misunderstood by readers, but over all, this book is well written and I recommend this book to kendo beginners, kids and instructors.