This publication, the 18th Edition US Army Operational Law Handbook, is a "how to" guide for Judge Advocates practicing operational law. It provides references and describes tactics and techniques for the practice of operational law. The Operational Law Handbook is not a substitute for official references. Like operational law itself, the Handbook is a focused collection of diverse legal and practical information. The handbook is not intended to provide "the school solution" to a particular problem, but to help Judge Advocates recognize, analyze, and resolve problems they will encounter in the operational context. The Handbook was designed and written for junior and mid-level Judge Advocates practicing operational law. The size and contents of the Handbook are controlled by this focus. Frequently, the authors were forced to strike a balance between the temptation to include more information and the need to retain the Handbook in its current size and configuration. Simply put, the Handbook is made for the Soldiers, Marines, Sailors, Airmen, and Coast Guardsmen of the military Judge Advocate Generals' Corps, who serve alongside their clients in the operational context. Accordingly, the Operational Law Handbook is compatible with current joint and combined doctrine. Unless otherwise stated, masculine pronouns apply to both men and women. The proponent for this publication is the International and Operational Law Department, The Judge Advocate General's Legal Center and School (TJAGLCS).