Vienna was a magnificent city in the last decades of the Austrian empire, a glittering centre of culture and opportunity. A young Jewish man from the provinces dreamed of a bright future there. He chose the new field of electricial engineering and became an immediate success. When the First World War broke out he established and commanded the Electrotechnic Group, providing electric defences for the army and all its electrical services. But the Hapsburg Monarchy fell and two decades later the Nazi German annexation of Austria posed an existential threat. This is the true story of Siegmund Defris, a man who was brilliant in peace and war.