First of all if you haven't read this series and you even kind of like historical fiction or mystery. RUN don’t WALK to pick up the first two books before this one comes out on February 28th! Here is my review for the second book The Body at the Tower if you need more convincing. The Traitor in the Tunnel is the third book in this series and trust me when I say I was DYING to read it. And while it was really, really good it wasn’t my favorite book of this series.Mary as usual was strong, smart, and resourceful. These are some of my favorite qualities in a heroine which is one of the reasons I like these books so much.James. Oh, James. I love James, but he was very different in this book than in the others and I don’t really know how I felt about that. Toward the end he started to act like the James I love and so I hope he will be the same in the next book.There were a lot of twists in this story which I really appreciate in mysteries. I also liked how the case started off really tame and then became more sinister. Something that was really different from this book and the others was the fact that Mary got to dive deeper into her heritage which I really enjoyed.Overall, not my favorite book of the series but I still definitely recommend it for any fans of historical fiction, mysteries, or just plain good books.