The Rook is what I would describe as Jason Bourne meets Men in Black meets X-Men with a touch of James Bond thrown in. It sounds like nonstop fun doesn't it? Well the beginning is very intriguing and had me turning the pages. However it became a less compelling read when the info dumps in the form of letters from the original Myfanwy (pronounced like Tiffany with an M and if you don't know what I mean by original, then you haven't read the book description) began to intrude on the present day action. I'm not sure why we had to have two missions interrupted by these letters. It was kind of aggravating to me, and just made the whole story less compelling which in turn made it seem like the book was far longer than it actually was. I didn't mind the letters themselves. They were vital to the story, but I just didn't always like where they were placed within the story.
There is one other small complaint. At one point Myfanwy discovers the identity of a traitor and has this traitor's cohort detained, but then doesn't mention it to anyone before going to a party where all of her coworkers are going including the traitor. Why wouldn't she have told the others immediately?
I actually liked Myfanwy a lot, at least the present Myfanwy. I don't think I would have liked her predecessor very much. I think the book had the right amount of humor and action. Parts of it still make me giggle if I think about them. Overall it was a fun read that was at times more compelling than others, and I would like to read the sequel. I just hope the continuity of the story is better.