by Cindy Neuschwander
Readers follow along with Sir Cumference and Lady Di of Ameter as their son Radius and his friend Vertex set out to find Edgecalibur. Filled with riddles and puns, the story is sure to delight students with some geometry background. Geehan's bright oil, acrylic, and pen-and-ink paintings include all the visual details that the text needs to help solve this geometrical mystery. If your students have enjoyed the first three books in the series, they will certainly want this one.