Had it not been for ball bearings, Schweinfurt might have remained a small town in Bavaria and escaped the notice of history. However, it was there in 1883 that a local mechanic, Friedrich Fischer, invented the machine that made possible mass production of ball bearings. In 1906, his son founded the Kugelfischer firm, which became the cornerstone of the industry. World War II created a huge demand for ball bearings. The German aviation industry alone used 2.4 million of them a month. Production was concentrated in Schweinfurt, where five plants turned out nearly two-thirds of Germany’s ball bearings and roller...