- Messner, Kate, Fergus and Zeke, 04
- Over and under the rainforest, by Kate Messner ; illustrated by Christopher Silas Neal
- Sloth wasn't sleepy, Kate Messner ; illustrated by Valentina Toro
- Escape from the great earthquake, Kate Messner ; illustrated by Kelley McMorris
- Messner, Kate, Ranger in time, 06
- Fergus and Zeke at the science fair, Kate Messner ; illustrated by Heather Ross
- Race to the South Pole, Kate Messner ; illustrated by Kelley McMorris
- Night of soldiers and spies, Kate Messner ; illustrated by Kelley McMorris
- Plagues and pandemics, Kate Messner ; illustrated by Falynn Koch ; with a special thanks to Ella Messner, who served as a researcher and contributor for this book
- Hide and seek, Kate Messner
- Messner, Kate, History smashers
- Sea monster's first day, by Kate Messner ; illustrated by Andy Rash
- Marty McGuire digs worms!, by Kate Messner ; illustrated by Brian Floca
- Over and under the waves, Kate Messner ; with art by Christopher Silas Neal
- Pearl Harbor, Kate Messner ; illustrated by Dylan Meconis ; with special thanks to Maggie Tokuda-Hall, who served as an early reader and consultant for this book
- Marty McGuire has too many pets!, by Kate Messner ; illustrated by Brian Floca
- Fergus and Zeke for President, Kate Messner ; illustrated by Heather Ross
- Journey through ash and smoke, Kate Messner ; illustrated by Kelley McMorris
- Breakout, Kate Messner
- Fergus and Zeke and the field day challenge, Kate Messner ; illustrated by Heather Ross
- Messner, Kate, Ranger in time, 03
- The Titanic, Kate Messner ; illustrated by Matt Aytch Taylor
- Marty McGuire, by Kate Messner ; illustrated by Brian Floca
- Disaster on the Titanic, Kate Messner ; illustrated by Kelley McMorris
- All the answers, Kate Messner
- Over and under the pond, by Kate Messner with art by Christopher Silas Neal
- Tree of wonder, the many marvelous lives of a rainforest tree, by Kate Messner ; illustrated by Simona Mulazzani
- The American Revolution, Kate Messner ; illustrated by Dylan Meconis
- Messner, Kate, Ranger in time, 09
- Capture the flag, Kate Messner
- Insect superpowers, 18 real bugs that smash, zap, hypnotize, sting, and devour!, by Kate Messner ; illustrated by Jillian Nickell
- Long road to freedom, Kate Messner ; illustrated by Kelley McMorris
- Tracking tortoises, the mission to save a Galápagos giant, Kate Messner with photographs by Jake Messner
- Solve this, forensics, Kate Messner and Anne Ruppert
- Danger in Ancient Rome, by Kate Messner ; illustrations by Kelley McMorris
- Messner, Kate, Ranger in time, 04
- The seventh wish, Kate Messner
- Wake up missing, Kate Messner
- The brilliant fall of Gianna Z., Kate Messner
- D-Day, battle on the beach, Kate Messner ; illustrated by Kelley McMorris
- The brilliant deep, rebuilding the world's coral reefs : the story of Ken Nedimyer and the Coral Restoration Foundation, by Kate Messner ; illustrated by Matthew Forsythe
- Sea Monster and the bossy fish, by Kate Messner ; illustrated by Andy Rash
- Messner, Kate, Over and under
- Up in the garden and down in the dirt, by Kate Messner ; with art by Christopher Silas Neal
- Sugar and ice, Kate Messner
- Messner, Kate, Fergus and Zeke, 01
- The next president, the unexpected beginnings and unwritten future of America's presidents, Kate Messner ; [illustrations by] Adam Rex
- The scariest kitten in the world, by Terrifying Kitten (with help from Kate Messner) ; illustrated by MacKenzie Haley
- Messner, Kate, Fergus and Zeke, 02
- Only the best, the exceptional life and fashion of Ann Lowe, by Kate Messner and Margaret E. Powell ; illustrated by Erin K. Robinson