This work provides an account of how, since early modern times, illustrations have increasingly played a primary part in books on art and architecture. Italian art of the period provides here a case study for the history of illustration from the 16th to the 20th century. The essayists consider illustrated texts on the art of Leonardo, Vasari, Serlio, Palladio, Teti and Andrea Pozzo and address issues seldom before covered. Each book illustration is carefully repositioned as a vehicle for ideas rather than as a transparent, passive visual form, dependent on its accompanying texts. In so doing, the contributors change completely our understanding of the role of images in books on art.