- Dolphins and sharks, a nonfiction companion to Dolphins at daybreak, 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
- Magic tree house incredible fact book, 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
- Leprechauns and Irish folklore, a nonfiction companion to Leprechaun in late winter, Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Magic tricks from the tree house, a fun companion to Hurry up, Houdini!, 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 of the Blue Dawn, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Carlo Molinari
- Horse 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
- Pandas and other endangered species, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Soccer, Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Snakes and other reptiles, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca
- Pilgrims, a nonfiction companion to Thanksgiving on Thursday, by Mary Pope Osborne and Natalie Pope Boyce ; illustrated by Sal Murdocca