Years ago I read a Philippa Gregory book that turned me off something awful. It was called The Wise Woman and it was fascinating and compulsively readable... until about halfway through, at which point the heroine became someone horrible and unlikable (obsessive, murderous, self-destructive, etc.), and finishing it was torture for me.

If that book was the unfortunate exception, I'm willing to try something else by her, but if this is pretty much her usual characterization arc, I'll avoid. Can you give me the skinny on that?