This book gave me a weird sense of Deja vu the whole time I was reading it. I've had it on my to-read list for a long time, so when my book club decided to read it, I was quite happy. But I feel like I've read it before. Perhaps that's why I only gave it three stars. I thought it was interesting, but I would have liked to know more about London Below. For example, Roman soldiers are mentioned and then we never hear about them again. Although there is quite a bit of world building, I would've liked more. All in all, a good book, but not my favorite. I still can't decide if I have read it once before or not, but that could contribute to how much I liked the book.