I was expecting to see some kind of grand finale for the third book, following the typical pattern of a strong start, dull but necessary middle, and a strong finish. This book was not strong, nor was it a finish, apparently. I'm not entirely sure on the status of a 4th book's existence, but this book left so many things open-ended that another book seems necessary, or this whole series just makes no sense. Some of the things really seemed contrived--like Alicia's dog and sudden status as not-really-Bobby's-girlfriend, which seemed to contradict with the previously set canon. The large scale impact of the invisibility still hadn't been dealt with, and Bobby and Alicia's story still felt like it needed more resolution. All this talk of the FBI and what would happen if they knew--now that would make for an incredible story, or even just an exploration of Bobby and Alicia's relationship, or both! Instead, neither aspect is focused on all that much, instead relying on centering the story around an invisible William. I did like the theme carried out throughout the book, the idea of "things that are", but like the previous two novels, it seemed lacking, and Clements is capable of doing so much better. I'm going to be sticking with his one-shot classroom stories.