A long time ago I read one or two of Cornwell's novels and wasn't particularly impressed. They reminded me a good deal of Kathy Reichs' novels. Occasionally Reichs' novels are worth reading, but on the whole they're extremely repetitive and I don't find I care at all about the characters.
This time, however, I've come away with a far better feeling for Cornwell's writing. I'm still not sure how I feel about having a medical examiner be the main character - a similar problem to Reichs' work, as well as Tess Gerritsen and a multitude of tv shows. Medical examiners, crime scene techs, lawyers, all these people are not detectives. They have their own jobs to do and they do them. I'm fairly sure that in real life these people rarely try their hand at police work on an active investigation. Which is part of the reason that I tend not to read these sorts of crime novels. I'm going to be making an exception for some of Cornwell's others though.
There's a very simple reason for this. The characters are engaging and believable. I care about them. I'm interested in what happens to them. Even the ones that I might not particularly like (actually, barring the niece I don't think I actually like any of them). Cornwell writes well and, more importantly, she writes engaging mysteries and doesn't screw up the science (reason number one that I can't watch any of those ridiculous tv shows without yelling at them or giving up in disgust). Another thing I particularly enjoyed about this book is the complete lack of Agatha Christieness. The bad guy is not someone that we've met. We don't know anything about him. While those sorts of books have their place and I really enjoy them, they're not always very realistic. In most cases of serial murder there's almost no chance that the bad guy is someone involved in the investigation, though those do make for fascinating stories. There's a realism to Cornwell's conception of crime that I really enjoy.