- Soccer, Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Ancient Greece and the Olympics, a nonfiction companion to Hour of the Olympics, y Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Tsunamis and other natural disasters, a nonfiction companion to High tide in Hawaii, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Leprechauns and Irish folklore, a nonfiction companion to Leprechaun in late winter, 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
- Polar bears and the Arctic, a nonfiction companion to polar bears past bedtime, 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
- Ghosts, a nonfiction companion to a good night for ghosts, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Dolphins and sharks, a nonfiction companion to Dolphins at daybreak, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Benjamin Franklin, 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
- Sabertooths and the Ice Age, a nonfiction companion to Sunset of the sabertooth, 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