Romania's Holy War rights the widespread myth that Romania was a reluctant member of the Axis during World War II. In correcting this fallacy, Grant T. Harward shows that, of an estimated 300,000 Jews who perished in Romania and Romanian-occupied Ukraine, more than 64,000 were, in fact, killed by Romanian soldiers. Moreover, the Romanian Army conducted a brutal campaign in German-occupied Ukraine, resulting in the deaths of thousands of Soviet prisoners of war, partisans, and civilians. Investigating why Romanian soldiers fought and committed such atrocities, Harward argues that strong ideology—a cocktail of nationalism, religion, antisemitism, and anticommunism—undergirded their motivation. Romania's Holy War draws on official military records, wartime periodicals, soldiers' diaries and memoirs, subsequent war crimes investigations, and recent interviews with veterans to tell the full story. Harward integrates the Holocaust into the narrative of military operations to show that most soldiers fully supported the wartime dictator, General Ion Antonescu, and his regime's holy war against "Judeo-Bolshevism." The army perpetrated mass reprisals, targeting Jews in liberated Romanian territory; supported the deportation and concentration of Jews in camps or ghettos in Romanian-occupied Soviet territory; and played a key supporting role in SS efforts to exterminate Jews in German-occupied Soviet territory. Harward proves that Romania became Nazi Germany's most important ally in the war against the USSR because its soldiers were highly motivated, thus overturning much of what we thought we knew about this theater of war. Romania's Holy War provides the first complete history of why Romanian soldiers fought on the Eastern Front.