The project combines material and art historical analyses on medieval book ornament, It aims to establish a new approach to this field of research. In the early and high Middle Ages, decorated books were created not as neutral storage devices to secure texts meant for reading, but as sacred objects. The distinctive decoration of the books used both in the liturgy and for private piety is characterized by the use of precious materials, and the different modes of evoking such materials on the body of the book. The appearance of this decoration shapes the surface textures of sacred scriptures on the outer covers as well as on the inscribed and illuminated pages within the books. To investigate the precious surface landscapes of medieval manuscripts, we have chosen four exemplary subcategories: gold and silver, purple, precious stones, and textiles. In all subcategories, we combine a close-up look at selected individual examples with a perspective that creates an overview of different geographic regions and time periods. Six questions common to the four subcategories are examined: 1) the topology, i.e. the distribution of the decorative elements and ornament on the three-dimensional body of the book; 2) the materials, techniques, and effects of the surface embellishments and their multi-sensory potential; 3) the art of writing – precious materials and script; 4) the iconicity of book ornament; and finally, 5) networks of actions and 6) discourses that determine the perception and semantics of the ornamentality of holy books.