The Monochrome of the Sala delle Asse is a portion of wall decoration left at the drawing stage and represents the roots of one of the sixteen mulberry trees that, regularly spaced on the walls of the room, intertwine above to create a polychrome arboreal pavilion on the vault. The Monochrome of the Sala delle Asse is a portion of wall decoration left at the drawing stage and represents the roots of one of the sixteen mulberry trees that, regularly spaced on the walls of the room, intertwine above to create a polychrome arboreal pavilion on the vault. The decoration of the room, which was never completed, is historically tied to the name of Leonardo da Vinci by a letter written in April 1498 by Gualtiero da Bascape, the secretary of Ludovico il Moro, to the duke of Milan, explaining that Lunedi si desarmara la camera grande da le Asse c[i]oe da la tore. Magistro Leonardo promete finirla per tuto Septembre. The room was subjected to radically changing fortunes over the centuries, and was later the object of two complex restoration campaigns, the first carried out between 1893 and 1902 by Luca Beltrami and the second between 1955 and 1956 by Costantino Baroni. This volume provides an account of the result of these restorations. It describes the complex diagnostic research and the technical assessments that form the foundations of a broader project for the conservation of the painted area. Text in English and Italian.