This is my favorite of the series so far. I loved this peek into Professor Fell's world, and Minx Cutter is my favorite new character. I did think Matthew did a pretty horrible job of becoming Nathan Spade and frequently wondered how he was fooling anyone. Again McCammon did a nice job of creating enough mystery and action to keep the reader engaged but mixing it with enough clues that the reader gets some satisfaction figuring things out just before the reveal. My biggest frustration with this novel is Matthew's relationship with Berry at the end. shaking head