Mummies and Pyramids (Magic Tree House Research Guides (Turtleback))

Titanic

Pirates

Knight's and Castles (Magic Tree House, #2)

Dinosaurs

Twisters and Other Terrible Storms (Magic Tree House Research Guide, Nonfiction Companion to Twister on Tuesday)

Rain forests

Space

Sabertooths and the ice age

Dolphins and sharks

13 ghosts