Armies and soldiers in ancient Greece and Rome. A bit various.
It opens with an analysis of how battle is treated in the Iliad, as a matter for heroes. Even when the massed troops fight well, the emphasis is on the wisdom of the hero who arrayed them. The trade-offs in standing your ground and fleeing, and how Ajax is assured that with all the Trojans he killed, no one will believe him weak when he leaves. Organization and battle in the Greek cities -- it was actually commented on by Greek authors that they didn't take advantage of terrain but lined up on good fighting ground to go at it -- and how Athens requiring drill caused many rich citizens to take up calvary. Refinements by Alexander.
And the conflicting love of virtus, manly prowess best shown in single combat, vs disciplina, much wider than our term, so that a soldier who fled battle could suffer less punishment than one who got orders to withdraw and wasn't prompt about it. Their battlefield formations, and changes up to the time of Julian the Apostate.