I posted about Tana French before, and her book In the Woods. The sequel, The Likeness, takes a major character from In the Woods and makes her the narrator and protagonist of this book. It is an audacious plot for a detective book about mistaken identity and undercover work. But French pulls it off very well. I've read two of her books, and both were quite quite good.
I recommend In the Woods, and then quickly picking up The Likeness. Mary's started the next book, which takes a major character from The Likeness and makes him the narrator. It will be interesting to see how long she keeps this up!