The Sayn Foundry in Bendorf, a German town on the Rhine near the Dutch border, is a fascinating example of complex technological thinking. Although the structural detailing is typical of its period (1830), Prussian engineer and iron founder Karl Ludwig Althans used and varied the many architectural and engineering models at hand in a sophisticated and complex building with structural elements that can be read as advertisements, machine parts, religious forms, or simply as building elements. The foundry, which is still standing, is just one of the many projects Peters examines in this broad synthesis of nineteenth-century technological thought and methods of design that form the basis of the modern built world. Through such examples, he traces the growth of technological thinking as one of our culture's chief modes of thought and establishes its primacy over other forms such as scientific or humanistic thinking as the major component of building design.