This is a class set of 15 books. The six horrible Herdmans, the worst kids in the history of the world, cause mayhem through the school year. Iowa Children's Choice Award 1996-1997. Interest Level: 3-6 Reading Level: 5.4 ATOS Book Level: 5.4 AR Interest Level: MG AR Points: 3 AR Quiz: 10212EN Reading Counts Level: 5.4 Reading Counts Points: 6 Lexile: 1020L Guided Reading Level: P Fountas & Pinnell: P.