|Abstract:||The US Army Air Corps was breaking new ground when it began daylight bombing of German targets in World War II. This was the first time daytime air warfare of such magnitude had been attempted. The British had given up bombing by daylight as being too dangerous and were bombing at night, when German anti-aircraft weapons and fighters were less effective. But, the bombing results were also less effective. Specific targets were seldom hit. The British were limited primarily to area bombing of cities. The Americans finally convinced Roosevelt and Churchill to allow them to bomb during the day, when target acquisition would be much more accurate. But, the proficiency of the German anti-aircraft artillery defenses and the fighters were also much more effective during daylight hours. There was no known way of coping with these defenses in a manner to minimize casualties while maximizing effectiveness of the bombing. As a result, the 8th Bomber Command, as the American bomber force at first was designated, engaged in a learning process to determine the best means of accomplishing its mission, with maximum efficiency and minimum loss of aircraft and lives. The first Bomb Groups to be deployed were the “guinea pigs” in this learning process and as a result suffered exceptionally high casualties. This account focuses on the 91st Bomb Group in describing the early missions (8 November 1942-17 April 1943 and the losses thereon.