The harrowing true story of Organisation Todt, the builders-turned-killers at the center of the Nazi war machine.

Whether it was military fortifications or grand cities designed to follow victory, Adolf Hitler turned to his loyal favorites for construction projects matching his imperial ambitions. Of the course of five years, he landed Organisation Todt, “the most impressive building programme since Roman times,” according to British intelligence. Headed by Albert Speer, the OT became a key partner to the SS and the Wehrmacht and led to the deaths of millions.

After Germany's defeat, Organisation Todt largely slipped under the radar. Unknown Enemy is the first major account of their operations, which grew out of the largest system of exploited labor since the Transatlantic Slave Trade. Charles Dick takes us to OT sites across Europe, from the Arctic circle to the Balkans and deep into what the Third Reich termed its “eastern Lebensraum,” to reveal how the organization boosted the German war economy by plundering raw materials and manpower, working thousands of prisoners to death within the SS-run concentration camp system and outside it. Drawing on devastating personal testimonies and extensive archival research, Unknown Enemy unveils how Germany's leading engineers and architects-neither soldiers nor policemen-got away with some of the gravest crimes ever perpetrated over the course of World War II.