This book reads like someone who has been doing this for several decades. It is very technical and sophisticated material. His passion for the arts shined through in each chapter I read. --Grandmaster Isaiah Gathings, author of The Book of Six Tenets: Martial Arts and Life, Soo Do Thai Instructor It's essential to be aware of your surroundings and know how to protect yourself. In Sphere of Influence: An Approach to Self-Defense, M.D. Holden discusses martial arts systems including Wing Chun and Shim Gum Do, to help you disable an attacker before a situation becomes more dangerous. By discussing sparring, hand-to-hand combat, and Wing Chun's relation to edged weapons, and stressing the importance of constant vigilance, M.D. Holden offers readers who are already well-versed in martial arts a well-rounded introduction to his approach to self-defense. M.D. Holden was a Wing Chun practitioner and martial artist of eleven years. He took his own life in August of 2015 at the age of twenty-seven. This book serves to honor his life and his life's work.