For decades, the Battle of the Somme has exemplified the horrors and futility of trench warfare. Here William Philpott argues that the battle ultimately gave the British and French forces on the Western Front the knowledge and experience to bring World War I to a victorious end. Philpott shows that twentieth-century war as we know it simply didn’t exist before the battle: new technologies like the armored tank made their debut, while developments in communications lagged behind commanders’ needs. Attrition emerged as the only means of defeating industrialized belligerents that were mobilizing all their resources for war. An exciting, indispensable work of military history, Three Armies on the Somme challenges our received ideas about the Battle of the Somme, and about the very nature of war.