The following list includes a few books published in Japan (and written in Japanese). Thanks to Jim Kelly for submitting images of these books.
2006 - NXT 1.0
LEGO MINDSTORMS NXT Orange Book by Yoshihito Isogawa is a color Japanese book, which can be purchased from amazon.co.jp. The book presents a number of robots with building and programming instructions as well as tons of incredible ideas. Also be sure to check out the author’s LEGO TECHNIC Tora no Maki book.
2006 - NXT 1.0
LEGO MINDSTORMS NXT Gray Book by Shinichiro Oba and Takuya Matsubara is another Japanese title that covers a wide variety of topics: programming, computer-aided design, mechanical tricks, and even trignometry. It also features one very large robot called Betarex that uses 2 NXTs and 5 motors.
2007 - NXT 1.0
LEGO MINDSTORMS NXT Black Book by Oba Shinichiro is yet another Japanese title that covers the NXT-G programming language and a series of 4 robots. It has both color and grayscale pages.