Mauro Bacci has been head of research at the Institute of Applied Physics “Nello Carrara” of the Italian National Research Council (IFAC-CNR), Italy. His main interest is in theoretical and applied spectroscopy. Since more than 25 years he is involved in diagnostics of objects of art using non-invasive spectroscopic instrumentations. Important masterpieces (by Masaccio, Giotto, Michelangelo, Leonardo among others) as well as modern paintings, stained windows and illuminated manuscripts were investigated non-invasively to characterize constituting materials and their preservation state. He gave also contributions to the monitoring of the environment where objects of art were on display.