Cryptid Sea Monsters: A Field Guide to 50 Fascinating Beasts

by Kelly Milner Halls, Rick Spears (illustrator)

Explore the fascinating world of sea monsters with this exciting guide to 50 aquatic cryptids by the creators of the bestselling Cryptid A Field Guide.

Cryptid Sea Monsters profiles 50 different aquatic cryptid mysteries around the world. Aspiring scientific explorers will discover that many ancient sea monsters turned out to be real creatures—like the oarfish, a real creature that inspired our legends about dragons—and learn about other cryptids that might one day turn out to be real.

Each cryptid has a reality rating of 1 to 6 to show whether it's more of a hoax or something that has been discovered and recognized by science.

This page-turning guide will inspire curious readers to investigate more on their own, and to understand the relationship between science and myth.

208 pages, Paperback

Published August 26, 2025

About the author

Kelly Milner Halls specializes in high interest, well researched nonfiction for young readers. Her books include TALES OF THE CRYPTIDS, SAVING THE BAGHDAD ZOO, IN SEARCH OF SASQUATCH and ALIEN INVESTIGATION. But she is also an avid YA fan and loves realistic fiction including GIRL MEETS BOY, the anthology she edited for Chronicle (January 2012). Her first short story is in that anthology. She hopes it won't be her last. When she's not writing or doing school visits, she works for her friend and mentor Chris Crutcher in Spokane.