Europe's Last Summer: Who Started the Great War in 1914? (2004) is a surprisingly readable history of the summer of 1914 and the steps that led to the War to End All Wars.
Says the publisher:
When war broke out in Europe in 1914, it surprised a European population enjoying the most beautiful summer in memory. For nearly a century since, historians have debated the causes of the war. Some have cited the assassination of Archduke Franz Ferdinand, others have concluded it was unavoidable.
. . . David Fromkin provides a different answer: hostilities were commenced deliberately. In a riveting re-creation of the run-up to the war, Fromkin shows how German generals, seeing war as inevitable, manipulated events to precipitate a conflict waged on their own terms. He moves deftly between diplomats, generals, and rulers across Europe, making the complex diplomatic negotiations accessible and immediate. Examining the actions of individuals amid larger historical forces, this is a gripping narrative and a dramatic reassessment of a key moment in the twentieth century.