I thoroughly enjoyed the book. Lady Di and Tom and quirky, enjoyable characters and are surrounded by a good supporting cast. The math is central to the mystery, and, quite frankly, was challenging (I took these classes a long time ago!). I got a chuckle out of the Rene D and Pascal characters as well. A clever attempt by the author, but I'm not sure how many middle school students will pick this up. (I am a middle school librarian).

Two kids, residents of the trailer-park island Adjacent, stuck between a trash heap and a nuclear power plant, try to figure out why residents of the town have gone missing. These kids are "unknowns" who don't count and sometimes aren't even seen, but once they start applying the problem-solving lessons taught them by the missing woman who used to help them with their homework, they start finding math clues, unlikely friends, and unexpected bravery.

Solving the problem of what's going on in adjacent requires algebra, cave exploration, geometry, rock-climbing skills, and neighborhood solidarity. Middle school level math is integral to the plot. Is it contrived? Yes, a bit, but it's also enjoyable. There are great characters here, from the spacey and visionary Tom Jones, to the determined Di to the various traumatized and outcast teens who join them to overcome Mr. Pink and his predatory security guards. Key to solving the mystery is the discovery that kids are a lot more than their reputation and the problem-solving tenets and approaches of Polya (Adjacent's general store carries his name) and others.

This book is for kids around 8-14 who like great characters and kids who like to puzzle out solutions or just to follow along as someone else puzzles them out.