Book excerpt: ADP 1-01 guides Army professionals (both Soldiers and Department of the Army Civilians) in their understanding of the entire body of professional knowledge and beliefs that shape the art and science of their profession. It addresses what doctrine is, why it is important, and which major ideas underlie it. The publication also discusses the most important taxonomies and terms used in the conduct of operations and the way they fit together as a single coherent whole. The principal audience for the ADP 1-01 is all members of the Army Profession. Commanders, staffs, and subordinates ensure that their decisions and actions comply with applicable United States, international, and in some cases host-nation laws and regulations. Commanders at all levels ensure that their Soldiers operate in accordance with the law of war and the rules of engagement. (See FM 27-10.)