The course attempts to systematically present a series of basic concepts that are usually dealt with in the architectural compositional process and that are related to the materiality of the architectural work, such as its structure, construction, and tectonic dimension, as well as the concept of decoration at a later stage. The choice of materiality in the design is a criterion that involves issues of technological and economic possibilities, but at the same time, it is also a criterion that determines the identity of the architectural work. The aim of the course is to highlight the role of materiality in the process of architectural composition and the contribution of materiality to the formulation of the idea of the architectural work. It attempts to raise questions such as at which stage of the compositional process the factor of the choice of materiality enters and what are the criteria of this choice. Issues such as the importance of the static carrier in the constitution of the compositional idea of space and in the definition of form, the relationship of the part to the whole, the articulation of detail and the assembly of different materials, but also issues such as sustainability and how materials age. Methodologically, a presentation of the historical appearance of the above concepts and their theoretical development in correspondence with philosophical currents is made. In the context of the course, students are asked to carry out an analysis of a building, based on the above concepts, explaining how the choice of materiality participates in the constitution of its compositional “immaterial” idea.