This book explores the influence of Helmuth von Moltke, Germany’s Chief of the General Staff between 1906 and 1914. Based largely on previously unknown primary sources, it analyses the General Staff’s role in military decision-making and Moltke’s relationship with Kaiser Wilhelm II, as well as the genesis of the Schlieffen Plan and Germany’s military and political reactions to the many pre-war crises. Moltke’s influence on Germany’s political decision-making was decisive, helping to foster an increasingly confrontational mood. The book takes specific issue with the common perception of Moltke as an ineffectual and reluctant military leader, remembered primarily for the defeat at the Battle of the Marne and his alleged adulteration of the Schlieffen Plan. It concludes that he was both bellicose and ambitious, hoping for war ‘the sooner the better’ and playing a crucial role in the outbreak and early months of the First World War.