Dennis O'Neil wrote both the novels (and he's a pretty good Batman writer IMHO), although I like the BB novel better than the TDK one, because it's got more backstory. In the BB novel you get parts of Ra's al Ghul's diary pertaining to Bruce and Ra's project to destroy Gotham, as well as a look into Bruce's life with the League of Shadows, in addition to the story from the film. In the TDK novelization, you get to know what happened to Scarecrow between the ending of BB and when he appears in TDK, but that's about it for extra info, the rest of the novel plays out pretty much exactly like the movie.