672 books • 43 series
Sharks and Other Predators (Magic Tree House Fact Tracker, #32) (Magic Tree House (R) Fact Tracker, #32)
Dogsledding and Extreme Sports (Magic Tree House (R) Fact Tracker, #34) (Magic Tree House Fact Tracker, #34) (Stepping Stone Book(tm))
Magic Tricks from the Tree House: A Fun Companion to Magic Tree House #50: Hurry Up, Houdini!