The purpose of this doctoral thesis is to reconsider the contribution of Frei Otto to architecture, taking as a basis his theoretical thought and his methodological and research experience carried out in close co-operation with the collaborators of the Institut für leichte Flächentragwerke (Institute for Light Structures) founded and led by him at the University of Stuttgart. It is proposed as a thesis the full strength nowadays of his experience and his theoretical thinking, far from the high tech assumptions, to which he has traditionally tended to be linked by critics, and a new consideration is suggested within the context of research about a suitable relationship between material and structural form, which has been a major feature among the most innovative engineers concerned with the design of forms with the new materials of the twentieth century.