672 books • 43 series
Magic Tree House Merlin Missions Books 1-4 Boxed Set (Magic Tree House (R) Merlin Mission)
Magic Tree House Merlin Missions Books 1-25 Boxed Set (Mth Merlin Mission) (Magic Tree House (R) Merlin Mission)
World War II: A Nonfiction Companion to Magic Tree House Super Edition #1 World (Magic Tree House (R) Fact Tracker, #36)