What is material as such in architecture? To contribute an answer to this question, the article examines sources from the eighteenth century to today. Discussing Vitruvius' remarks on materiality, Francesco Algarotti cites his Venetian teacher Carlo Lodoli in a 1756 pamphlet on architecture: “For which reason does stone not represent stone, wood [not represent] wood, each material itself and not another?” The paper illuminates the background of this citation, and its adoption and interpretation by successive architectural theorists, such as Gottfried Semper(“Brick should appear as brick, wood as wood, iron as iron”), Eugene Viollet-le-Duc, and Frank Lloyd Wright, the latter emphasizing the importance “to see concrete or glass or metal each for itself and all as themselves.” The thread continues with Adolf Loos' statement that no material “may lay claim for itself to the forms of another material” and the Bauhaus model as taught by Laszlo Moholy-Nagy. Further investigations will concern Louis Kahn's question “What do you want, brick?” and end with Peter Zumthor's discussion of the “reality of building materials.” Discussing rationalist and sensualist approaches to material characteristics such as inner structure and outer surface, the article compares divers positions concerning the question of what can be understood as concrete materiality.