Pinin Brambilla Barcilon is one of the world's foremost authorities on the conservation of Renaissance frescoes. She has published widely on the subject and is responsible for a number of important technical advancements in the field. For the last twenty years, she has served as the chief conservator of the project to restore the "Last Supper," Pietro C. Marani is a curator and Renaissance scholar who specializes in the life and production of Leonardo da Vinci. His books include "Leonardo: I Maestri, Leonardo and Venice," and "Leonardo: Catalogo Completo dei Dipinti," Harlow Tighe is a...