St. Mihiel represented the biggest staff problem attempted by the American Army up to that time. It was, of course, a battle which dwarfed any previous action in the military history of America. Compared to the battle of St. Mihiel, the whole Spanish-American War was a mere patrol encounter, and Gettysburg itself a minor engagement. With the force at his command, and the weapons, General Pershing could have annihilated the army of either Grant or Lee in half an hour. Some idea of the magnitude of the battle may be gathered from the report of General Pershing: that he had under his command approximately 600,000 troops, or four times the peace standing of the entire American military establishment before the war. It is difficult enough to move an army of that size, with its supplies and its guns, under any conditions, but the plan for the St. Mihiel offensive called for a surprise attack, and it was necessary to make all the troop movements at night. In spite of the vaunted efficiency of the German intelligence, there seems to be evidence that their high command had little inkling of the magnitude of the blow impending or the date on which it would fall. The St. Mihiel salient had been so long a fixture in the geography of the battle-lines that no change was expected. In preparation for the offensive the First Army was organized on August 10, under the personal command of General Pershing. Following this move the Americans took over part of the line. This became a permanent American sector. Pershing took command of the sector on August 30. At that time the sector under his command began at Port sur Seille, and extended through a point opposite St. Mihiel, then twisting north to a point opposite Verdun. The preparations for the offensive included, in addition to guns, men, and tanks, the greatest concentration which the American Army had ever known in transport, ambulances, and aircraft. Most of the planes in action were of French make, and some were flown by the French, but there were a few of our manufacture, for on August 7 an American squadron, completely equipped by American production, made its appearance at the front.