The book presents various sketches of fearsome critters from North American folklore, with descriptions by Cox preceded by full-page landscape illustrations by du Bois.

Like in a traditional field guide, each animal is assigned a Latin classification (by Sudworth), afterward noting their habitat, physical makeup, and behavior.

[3] Additionally, excerpts from Fearsome Creatures have been featured in a number of other publications, including: In the tradition of American tall tales and folklore, not all of the narrations are complete fabrications.

Likewise, in the sketch of the snoligoster there is a reference to Inman F. Eldredge (1883–1963), a Gifford Pinchot Medal awardee, who while pursuing an escaped fugitive in the everglades, encounters the dreadful swamp-wyrm which afterward devours the criminal.

[5] Other persons referenced in Fearsome Creatures are John P. Wentling (1878-1952),[6] who was Professor of Forestry at both the Pennsylvania State Forest Academy and University of Minnesota,[7] A.