Inside U by Master Byong Yu, Ph.D.
 

I'm not into the mystical side of martial arts and this book is anything but that. It's a good read. The first 2/3ds is a bio chronicling his life from childhood to the top of his martial art and down again to living on the streets. The remaining part is just plain common sense, how to be the best person you can be. Good stuff.

Master Byong's Web site