The Battle of Tannenberg saw the German Army inflict a humiliating and crushing defeat on the forces of Imperial Russia barely a month after the outbreak of World War I. Played out over larger distances than the battles on the Western Front, and with a greater disparity between the opposing forces, it rapidly evolved into a fluid and fast-moving campaign. Two Russian armies attempted to eliminate German forces in East Prussia, only to witness their forces collapse back in disaster, suffering huge losses of men and matériel. Michael McNally draws on original source material to describe the initial border engagements and the battles of Stallupönen and Gumbinnen, before moving on to explore the running battle of Tannenberg. Attention is given to the German speed of reaction, which overcame the Russian war plan of using overwhelming numbers to gain a quick victory before conducting further operations. This work also assesses the contribution that modern technology - such as railways, aerial reconnaissance, radio and telegraphy - made to the emphatic and unrivalled German tactical victory. Russia's defeat at Tannenberg, in contrast, would become emblematic of its experience during the conflict. Book jacket.