This field manual aims to provide techniques to assist planners in planning, coordinating, executing, synchronizing, and assessing military deception (MILDEC). While the means and techniques may evolve over generations, the principles and fundamentals of deception planning remain constant. FM 3-13.4 applies to all members of the Army profession: leaders, Soldiers, Army Civilians, and contractors. The principal audience for this publication is Army commanders, staffs, and all leaders. Commanders and staffs of Army headquarters serving as joint task force or multinational headquarters should refer to applicable joint or multinational doctrine concerning joint or multinational planning. Trainers and educators throughout the Army also use this publication as a guide for teaching MILDEC. Commanders, staffs, and subordinates ensure their decisions and actions comply with applicable U.S., international, and, in some cases, host-nation laws and regulations.