The Siegfried Line Campaign parallels the effort in Lorraine, following the U. S. First and Ninth Armies during the fall of 1944, through similar costly fighting. The narrative takes the reader from the first crossings of the German border on September 11, 1944, to the enemy's counteroffensive, which ended the campaign abruptly inside Germany along the Roer River on December 16. Highlighted are the piercing of the West Wall, the reduction of Aachen, the bitter fighting in the Huertgen Forest, and the operation of the First Allied Airborne Army in Operation Markey-Garden in the Netherlands. American participation in opening Antwerp and clearing the Peel Marshes is also included. The Siegfried Line Campaign is primarily a history of tactical operations in northwestern Europe from early September to mid-December 1944. In addition to the detailed coverage of the campaigns of the U. S. First and Ninth Armies and the First Allied Airborne Army, it sketches the concurrent operations of the Second British and First Canadian Armies. Organized into chapters at the corps level, the story is told primarily at division level with numerous descents to regiment and battalion and even at times to lover units. Logistics and high-level planning (for example, the controversy over single-thrust versus broad-front strategy) are treated where they affected the campaign. Staff operations at army or corps level are discussed when relevant to the development of tactical plans and operations.