About the book (from Wikipedia):
Musashi (Japanese: 宮本武蔵, Hepburn: Miyamoto Musashi) is a Japanese epic novel written by Eiji Yoshikawa, about the life and deeds of legendary Japanese swordsman Miyamoto Musashi.
The book follows Shinmen Takezō starting after the Battle of Sekigahara. It follows his life after the monk Takuan forces him to reinvent himself as Miyamoto Musashi. He wanders around Japan training young pupils, getting involved in feuds with samurai and martial arts schools, and finding his way through his romantic life.
It was originally released as a serial in the Japanese newspaper Asahi Shimbun, between 1935 and 1939. It has been re-released in book format, most of which are collections of several volumes, which compile the many newspaper strips. With an estimated 120 million copies sold, it is one of the best-selling book series in history.