'A History of War' explains the dark but compelling story of warfare, from its emergence in prehistoric tribal disputes, through great imperial and global wars, to present-day counter-insurgency and 'hybrid' conflicts. Two factors sit at the heart of this story: technology - including weapons, vehicle systems and vehicles and tactics. It charts the rise of the army, explaining how primitive tribal war parties evolved through seasonal levies and feudal armies to professional standing armies and mass conscription forces, with formal organisational structures.