Merriam Press World War 2 History Series. Historical Study German Report Series, Dept. of the Army Pamphlet No. 20-255. The German attack on Poland precipitated World War II, making the Polish campaign one of particular significance to the student of the 1939-45 conflict. The lessons learned by the German Army in its operations in Poland were put to use in the later campaigns against the western Allies, the Balkan states, and the Soviet Union. Poland also formed the testing ground for new theories on the use of armored forces and close air support of ground troops. The purpose of this campaign study was to provide the U.S. Army with a factual account of German military operations against Poland, based on source material from captured records then in the custody of The Adjutant General, Dept. of the Army; monographs prepared by a number of former German officers for the Historical Division, U.S. Army, Europe; and such Polish accounts as were available. 20 photos, 10 maps, 4 charts.