This is the official record of the restoration of Leonardo's painting "The Last Supper". It documents the cleaning and removal of the overpainting performed in other attempts at restoration, then looks at the watercolour additions of Barcilon, which were based on Leonardo's preparatory drawings, early copies of the painting and contemporary textual descriptions. The book details the reproduction process and distinguishes from the fresco Leonardo's hand from that of the restorers. Barcilon documents the technical aspects of the restoration, while art historian, Pietro C. Marani focuses on the history of the fresco, from conception through to restoration.