Doctrine provides a military organization with a common philosophy, a language,a purpose, and unity of effort. Tactics is the art and science of employing allavailable means to win battles and engagements. Specifically, it comprises theactions taken by a commander to arrange units and activities in relation to eachother and the enemy. This Field Manual (FM) 3-90 focuses on the tactics used to employ available means to win in combat. Those tactics require judgment in application. The ability to seize and secure terrain, with its populations and productive capacity, distinguishes land forces conducting decisive offensive and defensive operations. FM 3-90 provides a common discussion of how commanders from the battalion task force level through the corps echelon conduct tactical offensive and defensive operations and their supporting tactical enabling operations. It is not prescriptive, but authoritative.