Dolphins and sharks：a nonfiction companion to Magic Tree House #9: Dolphins at daybreak Dolphins and sharks：a nonfiction companion to Dolphins at daybreak Ninjas and samurai：a nonfiction companion to Magic tree house #5 : Night of the ninjas Mummies and pyramids：a nonfiction companion to Magic tree house #3: Mummies in the morning Mummies and pyramids：a nonfiction companion to Magic tree house # 3, Mummies in the morning Knights and castles：A nonfiction companion to Magic Tree House #2: The Knight at Dawn Polar bears and the Arctic：a nonfiction companion to Magic Tree House #12: polar bears past bedtime Dinosaurs：A nonfiction companion to Magic tree house #1: Dinosaurs before dark Warriors：a nonfiction companion to Magic tree house #31: Warriors in Winter Ninjas and samurai :：a nonfiction companion to Magic tree house #5 : Night of the ninjas /