The design development and combat history of some of the most technologically advanced fortress networks in Germany and France. Following the defeat of France in the Franco-Prussian War of 1870–71, the German Army began to construct a fortress line from Strasbourg to Luxembourg to protect their new territory, the centrepiece of which was the great Moselstellung (Moselle Position) of Metz / Thionville. Illustrated with rare photographs and full-colour cutaway artwork, this book examines the design and development of the fortress and analyses its use in combat, focusing particularly on the part it played in holding up General Patton's Third Army's advance across France in 1944.