In Hitler's Shadow War , WWII scholar Donald McKale contends that Hitler's persecution and murder of the Jews, Slavs, and other groups was his primary effort during the war, not the conquest of Europe. According to McKale, Hitler and the Nazi leadership used the military campaigns of the war as a cover for a genocidal program that centered around the Final Solution. Hitler continued to commit extensive manpower and materials to this "shadow war" even when Germany was losing the battles of the war's closing years. McKale explores the origins of the anti-Semitism that spread like wildfire through Germany before and during the Nazi's rise to power, and the failure of the Allies to perceive and stop the Holocaust even as they were defeating the Germans in combat.