Ancient Greece and the Olympics: A Nonfiction Companion to Magic Tree House (Magic Tree House Fact Tracker) $4.64 0375823786
American Revolution: A Nonfiction Companion to Revolutionary War on Wednesday (Magic Tree House Research Guide Series) $5.04 0375823794
Sabertooths and the Ice Age: A Nonfiction Companion to Magic Tree House #7: Sunset of the Sabertooth $6.99 0375823808
Polar Bears and the Arctic: A Nonfiction Companion to Magic Tree House $4.77 037583222X
Penguins and Antarctica: A Nonfiction Companion to Magic Tree House Merlin Mission #12: Eve of the Emperor Penguin $4.95 0375846646