Undercover Cat
Undercover Cat is a novel by Gordon and Mildred Gordon, about a cat who assists the FBI in tracking down a pair of bank robbers. It was first published in 1963 by Doubleday.
It has been adapted to a live-action Disney film twice, as That Darn Cat! (1965) and That Darn Cat (1997).
Two sequels were written by the Gordons: Undercover Cat Prowls Again (Doubleday, 1966) and Catnapped! The Further Adventures of Undercover Cat (Doubleday, 1974).