By its Cover (Commissario Brunetti #23) by Donna Leon; 2015. Softcover.

In the pages of Donna Leon’s internationally bestselling Commissario Guido Brunetti mysteries, the conversations of the Brunetti family have often turned to topics of art and literature, but books are at the heart of this novel in a way they never have been before. One afternoon, Brunetti gets a frantic call from the director of a prestigious Venetian library. Someone has stolen pages out of several rare books. After a round of questioning, the case seems clear: the culprit must be the man who requested the volumes, a visiting American professor. But the man fled the library earlier that day, and after checking his credentials, it becomes clear that he is not who he said he was. As the investigation proceeds, the suspects multiply. And when a seemingly harmless character turns up brutally murdered, Brunetti must question his expectations about what makes a man innocent, or guilty.