I have the impression I missed out by only listening to the audio of this children's book, but it was fun nonetheless. It is a nice little piece of speculative fiction about a grandpa scientist who has discovered the secret to reversing age. However, it stays securely grounded in children's-book territory rather then delving in to any of the interesting ideas it brushes up against; you definitely pick up on the mother's strained relationship with her scientist father, and you are faced forefront with the science vs humanities question. That was great. You also cooly see the amiably-divorced relationship of Ellie's parents and her Mom's boyfriend, and have a few hints of normal middle-school drama. Overall it is a positive piece advocating both the excitement of science and the crucial importance of humanity (from "humanities" like the stage theater of Ellie's parents to humanity like the importance of family). I won't hesitate to share this book with our daughter when she's, say, 8-11 years old and has the appropriate attention span for a story with a little more character-relations than magic or intrigue.