A set of 23 maps and cloth slipcase, some numbered and all marked 'SECRET!', issued by the German Army General Staff in Berlin in advance of the Sep. 1, 1939 invasion of Poland. Twenty-three (23) maps are included. Varying in size, with the largest of Warsaw, 33 in. x 33 in., showing over one hundred important buildings, factories and facilities in the city, Other maps include an 'Industry Overview' of Poland showing the location of other key industrial facilities and the items manufactured or mined thereat, with a second map showing these facilities around Kattowitz; road and railroad maps of the country; a map dividing the country into small numbered segments; and individual maps of the cities. All fit into a red cloth and heavy board slipcase, splitting at the seams. Overall very good.