War literally means fighting. However, fighting is also “a trial of strength of the moral and physical forces,” in which the “moral” aspect plays an important role (41). The modes of fighting have changed over time, especially with technology. However, equipment is “not essential to the conception of fighting” since “mere wrestling is also fighting” (41).

Tactics and strategy occupy distinct but related spheres as the “two activities mutually permeating each other in time and space” (46). Tactics pertain to the individual incidents of combat, whereas strategy combines them “with one another, with a view to the ultimate object of the war” (41, emphasis added). Tactics are “the theory of the use of military forces in combat” (42). Strategy is “the theory of the use of combats for the object of the war” (42). Certain activities in a war may serve both tactical and strategic purposes.

The art and science of war once described the “totality of those branches of knowledge and those appliances of skill occupied with material things” (46). These included building fortifications as well as army organization and its movement.