Yeon Hwan Park was the undefeated Korean national champion of Tae Kwon Do from 1971 to 1975. He has coached the United States Tae Kwon Do team and the United States Olympic and Pan American Tae Kwon Do teams. He is the president of the United States Tae Kwon Do Union and publisher of USA Tae Kwon Do Review. His previous books include
Tae Kwon Do,
Tae Kwon Do: My Life and Philosophy, and
Tae Kwon Do for Children. He lives in New York.
Jon Gerrard graduated with a degree in psychology from Princeton University, where he also served as president of the Tae Kwon Do Club for two years. For more than ten years he has taught martial arts to law enforcement agents. He is currently a teacher at a private school and a martial arts coach. He lives in New York.