Kendo and Related Books

Here are some in-print books that you can get directly through Amazon.com:

Books from Amazon.com on Kendo
Kendo: The Definitive Guide	Complete Kendo
This Is Kendo: The Art of Japanese...	The Sword of No-Sword: Life of the...
The Heart of Kendo

Books from Amazon.com on Kata
Looking at a Far Mountain: A Study of...

Books from Kendo World
Kendo Kata: Essence and Application	Budo Perspectives

Books from Amazon.com of general interest...
The Japanese Sword: The Soul of the...	The Japanese Sword:...

If you are looking for out of print books you can try a second-hand source like the Antiquarian Book-Seller's Exchange. You can put in requests for books as well as search a growing, global network of book sellers.