Common German practice in all types of military operations, as enunciated in their field service regulations, calls for the maximum use of surprise, which in turn involves secrecy, deception, and speed of execution. During the early European campaigns of the present war, because of overwhelming initial aerial superiority, the Germans did not pay too much attention to the camouflage of AA positions and to other passive defense practices. In later and present campaigns, however, the Germans have not always had definite air superiority, and they have used many passive means of deception and concealment, such as camouflage and erection of dummy gun positions and objectives, to protect themselves from aerial observation and to assist in maintaining the secrecy of their dispositions and operations. In the Libyan Desert, much ingenuity has been shown in concealing AA weapons, especially through dummy gun positions. Vehicles as well as guns are camouflaged with nets and local material, and resort is had to as much dispersion as possible under the tactical circumstances. In one operation in July of 1941, German guns were located among abandoned Italian artillery which had been left there from previous battles. These guns were not noticed until they opened fire.[11]