This book provides a detailed operational study of the St. Mihiel Offensive, conducted between 12 and 16 September 1918. It examines the first major independent offensive led by the American Expeditionary Forces (AEF) under General John J. Pershing during the final phase of the First World War on the Western Front. The author analyses the strategic importance of the St. Mihiel salient, a heavily fortified German position that had remained largely unchanged since 1914. The study covers planning, coordination between American and French forces, battlefield execution, and the rapid collapse of German defensive positions during the offensive. Special attention is given to terrain analysis, logistics, troop movements, and command decisions, as well as the broader operational consequences that set the stage for the subsequent Meuse-Argonne Offensive. This volume is part of the Battleground Books series, which focuses on detailed battlefield studies combining historical narrative with maps and contemporary imagery. It is designed both as a scholarly military history and as a practical guide for understanding the modern landscape of the battlefield. (AI-generated content description)