Mark Hatmaker is the author of Boxing Mastery, More No Holds Barred Fighting: Killer Submissions, No Holds Barred Fighting, and No Holds Barred Fighting: Savage Strikes. He has extensive experience in the combat arts, including boxing, wrestling, and jiu-jitsu, and is a highly regarded coach of professional and amateur fighters, law enforcement officials, and security personnel. He is the founder of Extreme Self Protection (ESP), a research body that compiles, analyzes, and teaches the most effective western combat methods known. He lives in Knoxville, Tennessee.