The science fair is a nice touch, since it is a very common occurrence in middle school that shows up rarely in the literature. While this is primarily science fiction (due to Melvin's experiments with turning himself younger), there are also a lot of good science topics covered. Holm has an interest in STEM topics, and teachers are always asking me for books that include science, so I'm always glad to find new ones.
Younger readers might be warned about the death of Jonas. It was handled well, but it was a bit odd that we don't know quite what happened. Was he hit by a car? I realize that this was so that they could inject him with the axolotl and have some hope, but it was an odd note in an otherwise upbeat title. .