The seventeenth book: #17 The Trials of Persiles and Sigismunda - Miguel de Cervantes
Although de Cervantes considered this his better work, I'm not so sure. One big attraction of Don Quixote was how normal it was - it feels like an early novel about ordinary people, rising above their stations, but really dealing with normal subjects. His Persiles, instead, takes from Greek stories and chivalric romances and tries to be its own version. And, well, that style just doesn't work for me. I was honestly glad when I was done this time... not a good sign.