This book is an examination of the minimum performance standard developed in collaboration with the Office of Law Enforcement Standards to determine the requirements and test methods for the ballistic resistance of personal body armour intended to protect against gunfire. The standard discussed specifies the minimum performance requirements that equipment must meet to satisfy the requirements of criminal justice agencies and the methods that shall be used to test this performance. Body armour manufacturers and purchasers may use this standard to help determine whether specific armour models meet the minimum performance standards and test methods. The National Institute of Justice standards are subject to continued research, development, testing, review, and revision and are re-evaluated and modified as necessary.