- The Random House book of Bible stories, retold by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Michael Welply
- Snakes and other reptiles, a nonfiction companion to Magic tree house #45: A crazy day with cobras, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Ancient Greece and the Olympics, a nonfiction companion to Hour of the Olympics, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Leonardo da Vinci, a nonfiction companion to Magic tree house #38: Monday with a mad genius, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Sharks and other predators, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Carlo Molinari
- Ninjas and samurai, a nonfiction companion to Magic tree house #5 : Night of the ninjas, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Warriors, a nonfiction companion to Magic tree house #31: Warriors in winter, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Isidre Monés
- Abraham Lincoln, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Rags and riches, kids in the time of Charles Dickens : a nonfiction companion to A ghost tale for Christmas time, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Heroes for all times, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- American revolution, a nonfiction companion to Revolutionary War on Wednesday, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Pilgrims, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Soccer, Mary Pope Osborne and Natalie Pope Boyce
- Dolphins and sharks, a nonfiction companion to Magic tree house #9 : Dolphins at daybreak, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Ghosts, "A nonfiction companion to Magic Tree House #42: A Good Night for Ghosts.", by Natalie Pope Boyce ; illustrated by Sal Murdocca
- Leprechauns and Irish folklore, by Mary Pope Osborne and Natalie Pope Boyce
- Sea monsters, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Dog heroes, a nonfiction companion to Magic tree house #46: Dogs in the dead of night, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Ancient Rome and Pompeii, a nonfiction companion to Vacation under the volcano, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Narwhals and other whales ;, a nonfiction companion to Magic Tree House #33: Narwhal on a sunny night, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Isidre Monés
- Horse heroes, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Penguins and Antarctica, a nonfiction companion to Eve of the emperor penguins, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Sea monsters, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Pandas and other endangered species, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Sabertooths and the ice age, a nonfiction companion to Magic tree house #7: Sunset of the sabertooth, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Polar bears and the Arctic, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Benjamin Franklin, a nonfiction companion to Magic Tree House #32, To the future, Ben Franklin, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Isidre Monés
- Rags and riches, kids in the time of Charles Dickens, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Magic tricks from the tree house, a fun companion to Magic Tree House #50 : hurry up, Houdini!, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- World War II, a nonfiction conmpanion to Magic tree house super edition #1 : world at war, 1944, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Carlo Molinari
- Vikings, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Carlo Molinari
- Tsunamis and other natural disasters, a nonfiction companion to magic tree house #28, High tide in Hawaii, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Wild West, a nonfiction companion to Magic tree house #10: Ghost town at sundown, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Isidre Monés
- Ghosts, a nonfiction companion to A good night for ghosts, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Dog heroes, a nonfiction companion to Magic tree house #46: Dogs in the dead of night, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca