Books are a good source for the warrior to enhance his/her training. There are many books out there on the subject of martial arts. The following is but a short list of some of the ones that Sabumnim Niemi recommends, in no particular order (if you have one of your favorites that you think should be on this list, send sabumnim an email, he may add it to the list!)
The Book of Five Rings - by Miyamoto Musashi
A classic treatise on strategy that every martial artist should read (probably 3 or 4 times, as it is hard to grasp!)
The Art of War - by Sun Tzu
Another strategy classic!
Moo Duk Kwan Tae Kwon Do: Korean Art of Self-Defense - by Richard Chun
This is the style that Spirit Warrior Martial Arts Academy is based on. Its a two volume set written by one of the pioneers of bringing taekwondo to America.
Taekwondo: Ancient Wisdom for the Modern Warrior - by Doug Cook
Written by a student of Richard Chun, this is one of the better books on the principles and philosophy of taekwondo.
Beyond the Known - by Tri Thong Dang
A cool book about the true purpose of the martial arts, told as a fictional story. Only about 150 pages long, but so much to learn from it!
Living the Martial Way - by Forrest E. Morgan, Maj USAF
Although I don't agree with everything the author says, this is one of the best books I have ever read on the true way of the warrior. I highly recommend it!!
On the Warrior's Path - by Daniele Bolelli
Another great read on the way of the modern warrior.
Relax Into Stretch - by Pavel Tsatsouline
A great book on how to stretch CORRECTLY. Most martial arts schools and athletic coaches in America do not understand the proper way to stretch. This book is based on techniques used in Eastern Europe for decades. Highly recommended for every martial artist.
Gates of Fire - by Steven Pressfield
A five star book about the 300 Spartans at the battle of Thermopylae. A fictional story based on historical fact. Mr. Pressfield did extensive research into the truth of the Spartans. A great study of a warrior society.
Among Warriors: A Woman Martial Artist in Tibet - by Pamela Logan
I really enjoyed this book. A true story about a woman who is a 3rd degree black belt in karate. She traveled to Tibet and searched for the Khampa warriors, who for 25 years fought against the Chinese occupation.
The Power of Now - by Eckhart Tolle
This is an excellent book on learning how to "shed the ego". Explained in simple to understand language, it cuts through some of the mumble jumble of eastern thought and philosophy and presents the concepts for the western mind. Highly recommended!