Not everyone who reads this book would be familiar with the structure of the First AIF in 1916, when the Battle of Pozières commenced. These notes are intended to provide a basic understanding of that military structure.

The main component of any army is the infantryman, the soldier who, with rifle and bayonet, or, in some cases, with a machine gun or grenade, has the task of seeking out and killing the enemy. Without the infantryman wars cannot be fought. But to carry out his role the infantryman needs support from other arms: artillery, engineers, armoured units (although these were not engaged during the Australian attacks at Pozières), field ambulance and the ordinance units that ensured food, ammunition and supplies reached the front. Specialised units of machine-gunners and mortar crews also provided the infantry with support in the front line while intelligence units and cartographers assessed information in order to understand what was happening on the battle front.

By the time the Battle of Pozi`eres commenced, on 23 July 1916, the AIF consisted of five infantry divisions, together with supporting units. Three of those divisions, the 1st, 2nd and 4th, took part in the fighting at Pozières. The 3rd Division under Major-General John Monash was undergoing training in Britain, and the 5th Division, commanded by Major-General James Whiteside McCay, had been devastated by the fighting at Fromelles on the night of 19/20 July and took no part in the action at Pozi`eres.