George Leonard drew the principles of this book from his knowledge of the philosophy of (zen) and his experience in martial arts, especially the ecido, which is the most difficult martial arts- and he has been practicing it throughout his life and imitated the black belt, and this book was written to demonstrate that it could reach and maintain a high level of ingenuity And professionalism in what you do with a deep sense of verification and contentment without your endeavor is like an endless feverish race.