 The Intelligence Corps staff devoted considerable time and effort during the pre-invasion period conducting a massive "background study" into the organization of the German Army, its weapons, tactics, equipment, civil administration and Party organization, the language, the country and its people.Anything and everything that was considered useful and helpful towards completing the preparation of the invasion plans was actioned.The intensity with which this preparation was undertaken bore fruit, as evidenced by the tactical surprise which the actual assault achieved.