The Best Book in the World

I get annoyed at little things. Here's the latest. I don't know how many times I've read, in textbooks and even academic studies, that according to Cervantes, Tirant lo Blanc was the best book in the world. But even a rudimentary knowledge of narratology ought to make it clear that Cervantes says nothing of the sort; the priest says it. It may be true, and Cervantes may really have thought that, but the priest says it.