80 books • 17 series
Book #2: Children's Encyclopedia of Space
Book #4: Children's Encyclopedia of Science
Book #11: Children's Encyclopedia of Science Experiments
Book #1: Did Cavemen Brush Their Teeth?
Book #3: What Does the Moon Taste Like?
Book #4: What Makes You Hiccup?
Book #7: Why Don't Sharks Have Bones?
Book #6: Miraculous Magic Tricks: Set 2