Miyamoto Musashi's Book of 5 Rings - Analysis of the book with extensive English test, plus the entire text in Japanese. - http://artofwar.thetao.info/japan/
A Book of Five Rings - Go Rin No Sho - Complete text of a translation by Victor Harris of Musashi's most famous work. - http://www.samurai.com/5rings/
Wikipedia: Miyamoto Musashi - Extensive article with references and works. - http://en.wikipedia.org/wiki/Miyamoto_Musashi