Rather basic, as history writing goes, but lays out what the author could find of the facts of the case clearly enough. I read it, of course, because of having loved "The Ring and the Book". I'm not sure what it does to my thinking about that poem to know that Browning was either drastically misinformed about many of the facts of the case or deliberately distorted them (for just one example, Giuseppe Caponsacchi was not a priest!). He seems indeed to have been relying on just the kind of rumor-mongering he scorned in some monologues. So, the reflections on the purposes of writing historical fiction have to be informed by the miswriting of history.