This course looks in depth at the means by which architects combine various materials in order to express an architectural intent. Properties of materials are discussed, as well as the major tectonic hierarchies: rigid and sheet materials, frames and skins, heavy and light volumes, bearing walls and screens. Methods of expressing joints between materials (hidden, expressed, revealed, exaggerated, trimmed) are also explored. Students are asked to carry out a number of tectonic and material design exercises, taken from and in connection with their studio work of the same term. This course is complementary to ASC 623, which looks at many of the same issues from a technical standpoint.