- Horse heroes, 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
- Dog heroes, 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
- Dogsledding and extreme sports, a nonfiction companion to Magic tree house #54, Balto and the blue dawn, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Carlo Molinari
- 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, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca