For those interested in the history of Japanese martial arts another fine book is ARMED MARTIAL ARTS OF JAPAN: SWORDSMANSHIP AND ARCHERY by G. Cameron Hurst. The publisher included a good introduction:
“This unique history of Japanese armed martial arts…focuses on traditions…from ancient times to the present…[It] provides an overview of martial arts in Japanese history and culture, then closely examines the transformation of these fighting skills. ..Hurst investigates the changes that occurred when the military training that was no longer necessary took on the new purposes: physical fitness, spiritual composure, character development, and sport…”