This book is about historical ornamentations applied in Iranian architecture. In particular, the book addresses those types of ornamentations that function more than attractive and beautiful decorations. These types of ornamentations are known as “Āmood” in the literature of Iranian traditional architecture. Some Āmood types operate as thermal or moisture protectors, acoustic absorbers or diffusers, flooring system, structural components or building enclosure elements. The span of the study includes architectural works within the current limits of Iran through the ages from the primitive civilizations, when human began to paint in their living caves, to the end of Qajar dynasty (1925 C.E.). The first chapter of the book begins with a discussion about the notion of art in Iranian architects’ perspective. Then, it moves toward pointing the notion of light in the second chapter. There, the different ways of providing daylights in diverse buildings are mentioned and a number of relevant building components such as windows (Orosi), skylights (Hornū), and shading screens are described. In the third chapter patterns used in Iranian Āmood are introduced through four categories: geometric patterns and grids (Gereh), vegetal and floral patterns (Eslimi and Khatai), animal figures, and human images and configurations. Before stepping into the introduction of ornamentation categories the use of colors is discussed in the fourth chapter.