On the more philosophical side, a good introduction to Zen philosophy is "Zen in the Martial Arts" by Joe Hyams. This book covers the lessons and experiences of the author during his 25 years of martial arts training. He has studied with many masters over the years, the most famous being Bruce Lee. Hyams' training covers most of the well known disciplines, including Karate, Akido and Kung Fu. He thoroughly covers the often ignored subject of philosophical training in martial arts. Many of the lessons are from practical, everyday events, making them much easier to relate to. I recommend to anyone who wants to make their life run smoother and be more fulfilling, read this book.