In the middle of Campo Santo Stefano stands a marble gentleman with a long beard, his arms crossed and a scroll in his hand. The dedication on the pedestal says he is Nicolò Tommaseo — with a single c. But ask anyone what the monument is called and the answer will always be the same: el cagalibri. You only see why by walking round it: at the back, beneath the hem of his coat, juts out a pile of books carved in marble.