My favorite (copied from Wikipedia): The Unfettered Mind (Japanese: 不動智神妙録 Fudōchi Shinmyōroku) is a three-part treatise on Buddhist philosophy and martial art

My favorite (copied from Wikipedia): The Unfettered Mind (Japanese: 不動智神妙録 Fudōchi Shinmyōroku) is a three-part treatise on Buddhist philosophy and martial arts written by Takuan Soho, a Japanese monk of the Rinzai sect. The title translates roughly to "The Mysterious Records of Immovable Wisdom". The treatise was written as correspondence to Yagyū Munenori, inheritor to the Yagyū Shinkage-ryū school of swordsmanship. Written for the laity, the book makes little use of Buddhist terminology, but instead focuses on describing situations followed by an interpretation. Its contents make an effort to apply Zen Buddhism to martial arts. Available in PDF form here: http://www.daikonforge.com/downloads/TheUnfetteredMind.pdf http://www.daikonforge.com/downloads/TheUnfetteredMind.pdf