Miyamoto Musashi (1584-1645) was an undefeated samurai during the 17th century in Japan. He was orphaned by the age of 7 and became a swordsman, killing his first man at the age of 13. Eventually he fought some 60 duels without ever being defeated. By the end of his career, he had become so expert and dominant that he would fight his opponents with nothing but a stick. Then in 1643, he retired to a contemplative seclusion in a cave, where, just before his death, he wrote this book.