Introduction to Okinawa Kobudo by The Master

Here is the book written by The Kobudo Master, Masahiro Nakamoto Sensei, the first 10th Dan in Japan.
http://www.theokinawan.com/kobudobook.php

History of Okinawa Karate Kobudo

Here you would like to find the history of Okinawa Karate and Kobudo :
http://www.okinawabbtv.com/culture/karate/okinawakarate_e/history/e_history002.html