Gr 3-6 Sir Cumference returns in this tale that introduces readers to the concepts of perimeter and area. As in the previous books, Neuschwander's characters have names that play with mathematical terminology. In this adventure Per visits his uncle and aunt (Sir Cumference and Lady Di of Ameter). After learning a game involving inners and edges, she and her cousin Radius become embroiled in a mystery with a secret message and a threatening sea serpent. To solve it, the youngsters must travel to the Isle of Immeter and use a series of geometric formulas to tame the sea serpent and bring peace to the area. Readers already familiar with these formulas will have the most ease understanding and solving the mystery. Teachers introducing the concepts of perimeter and area might find the book useful. Libraries that own the four earlier books in the series will want to consider adding this latest adventure to their collections.Maura Bresnahan, High Plain Elementary School, Andover, MA[Page 108]. Copyright 2006 Reed Business Information.