Marginalia has a special position in the visual culture of Iran. We see the presence of this visual element in all works of art. including in relief motifs, pottery and metal vessels, carpets, clothes, textiles, architecture and decorations related to it such as tiling and especially in the art of book design in Iran. Marginalization in Iranian works of art has an independent identity and various functions in different periods of development. The purpose of this research is to achieve the aesthetic capabilities of marginalia in the book-arrangement tradition of the Islamic era of Iran, and especially in the book-arrangement art of the Ilkhanid, Timurid and Safavid periods, and it seeks to answer this question by examining the marginalia in the book-arrangement tradition of the Ilkhanid, Timurid and Safavid periods. What aesthetic features can be identified? This research is fundamental in terms of its purpose and was carried out with a descriptive-analytical approach, as well as the collection of information through documentary and library methods. The results of the research indicate that Marginalia is an aesthetic concept and an important element of Iranian art, derived from its philosophical principles and thoughts, rooted in Eastern beliefs and worldview. Among these concepts and indices, creating a safe space, highlighting the subject and emphasizing it, directing the viewer's gaze inwardly into the frame were noted. Evaluating the characteristics of this visual element, we discovered the artist's adherence to principles such as the principle of squared shape ominousness, hierarchical principle, and adherence to a specific color system, all of which are aesthetic principles of Iranian art. The aim of using these principles has been to better present the artwork, prepare the viewer's gaze for entry into the main text, create a space for visual calm and silence, and act as a mediator and connector between the viewer and the artwork.