The Book of Five Rings by Miyamoto Musashi

Miyamoto Musashi was a Japanese swordsman, philosopher and ronin (masterless samurai). Musashi died of what is believed to be thoracic cancer, in 1645 -- undefeated, having fought 61 duels. His work The Book of Five Rings is a treatise on his unique style of swordsmanship, strategy, and tactics.