This book is kind of a follow up to Superposition. It features the Kelley family. Also, I can't forget the varcolac. The reason I say that this book is "kind of" because if you have not read Superposition, then you still will be drawn to this book but I can tell you that after finishing this book, you will want to go back and pick up a copy. I could not stop reading this book. When I did put it down for a moment, I was already half way done. Of course, when I could, I rushed back to this book and finished the last half just as quickly as I did the first half. I absolutely love this book and books from Mr. Walton. I can't wait to read the next book and learn more about the varcolac. For a fan of sci-fi books this is a great book. Although I would classify this book as a quantum physics book. Which if this is what all these types of books are like, than sign me up.