This comprehensive biography traces the life and works of Robert Maillart, one of the most important engineers and designers of the twentieth century. His career developed around a central issue of modern technological society: the debate between two antithetical views of engineering opposing applied science, which relied on general mathematical theories for understanding structures against design, which Maillart championed. Maillart considered structures not merely works of utility but also as works of art. As utilitarian objects, he created a series of innovations of lasting significance. Aesthetically, Maillart shaped his three innovations in concrete to create surprising and often stunning new forms. Providing an analysis of these innovations, this biography also connects Maillart's aesthetic ideas with the private and professional context in which he worked.