After Fifth Grade, the World!, by Claudia Mills

Heidi (or HP as she likes to be called) has the meanest fifth grade teacher in the world, a friend who won't talk to her own parents, and parents herself that are the biggest slobs. But HP won't falter at a challenge. Instead, she develops schemes to change the world and learns some lessons about change and working with people.

A charming and functional middle school read. Very dated, but enjoyable. Like many of Mills's books, the adults seem a bit overly mean (ironic since exaggerated adults are more a trademark of teen reads) and that can be a bit distracting. But HP is a typical Mills heroine -- strong willed and brave.