At the beginning of the First World War, Germany elected to mass most of its armies on what became the Western Front. The limited forces in the East, on the Russian frontier, were given an economy of force mission. Badly outnumbered by their Russian opponents, German forces in the east faced a risky fight. In this Osprey Campaign series book, author Michael McNally demonstrates how German tactical flexibility and superior intelligence gathering enabled them to turn the tables on the Russian army at Tannenberg. The text has lots of period photographs and modern illustrations and battle diagrams. The battle diagrams are particularly essential for following a confusing fight. Recommended to students of the First World War.