The basis for our understanding of Leonardo’s theory of art was, for over 150 years, his Treatise on Painting, which was issued in 1651 in Italian and French. This present volume offers both the first scholarly edition of the Italian editio princeps as well as the first complete English translation of this seminal work. In addition, It provides a comprehensive study of the Italian first edition, documenting how each editorial campaign that lead to it produced a different understanding of the artist’s theory. What emerges is a rich cultural and textual history that foregrounds the transmission of artisanal knowledge from Leonardo’s workshop in the Duchy of Milan to Carlo Borromeo’s Milan, Cosimo I de’ Medici’s Florence, Urban VIII’s Rome, and Louis XIV’s Paris.