Trench warfare
Trench warfare prevailed on the Western Front from late 1914 until the Germans launched their Spring Offensive on 21 March 1918. After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals, to be decided by attrition. Frontal assaults, and their associated casualties, became inevitable because the continuous trench lines had no open flanks. Casualties of the defenders matched those of the attackers, as vast reserves were expended in costly counter-attacks or exposed to the attacker's massed artillery. There were periods in which rigid trench warfare broke down, such as during the Battle of the Somme, but the lines never moved very far. The war would be won by the side that was able to commit the last reserves to the Western Front.
The Guns of August
"The Guns of August" thus provides a narrative of the earliest stages of World War I, from the decisions to go to war, up until the start of the Franco-British offensive that stopped the German advance into France. The result was four years of trench warfare. In the course of her narrative Tuchman includes discussion of the plans, strategies, world events, and international sentiments before and during the war.