The Clue of the Tapping Heels is the sixteenth volume in the Nancy Drew Mystery Stories series.
Nancy, Bess, and George have become tap-dance enthusiasts. Nancy meets an eccentric retired actress, Miss Carter, who owns a large number of cats. Nancy attempts to solve a strange tapping sound at the woman's house. Miss Carter's finances are in a poor state, due mostly to the manipulations of a crook. Meanwhile, Nancy seeks to restore a former suitor of Miss Carter to favor. The story outline was completed by Edna Stratemeyer Squire, and was written by Mildred Wirt Benson, the series' primary ghostwriter. Mrs. Squire is noted to have unusual tastes in plot devices, and this is evident in the unusual action, chapter climaxes, and various other events in the book.
In a humorous but uncharacteristic, Nancy and George are drugged by inhalants at a downtown restaurant. In the climax, Nancy is captured, and left bound inside the cabin of a large boat. She taps Morse code with her high-heeled oxfords to seek aid, before revealing the mystery's solution. It is this scene which is illustrated in the book's frontispiece.
Nancy is appearing as a tap dancer in a charity show, all the while with chums Bess and George, investigating strange tapping sounds at the elderly Mrs. Purdy's home. Purdy, like the character of the same name in the original version, is a cat enthusiast, only this time she owns mostly valuable breeding stock. Nancy determines there is a hoax going on, there are attacks at the charity show, and the mysterious tapping sounds are Morse code.
The original Russell H. Tandy cover art shows an animated and visibly angry Nancy, accompanied Bess, and George seizing a ladder at Nancy's house, by moonlight. Discussions draw the conclusion so many elements were incorrect because the publisher's art department dictated the scene to show Nancy with her friends; the house doesn't match the description of Nancy Drew's home. The revised cover artwork by Rudy Nappi for the 1962 picture cover, shows the same scene, corrected to match the actual text, but lacking action. Nancy, alone, sees the ladder outside her home at night. For the 1969 revised edition, the cover art is very vivid and somewhat psychedelic, with images of Nancy tap-dancing, and a head shot underneath a giant Persian cat head, all on a sunflower-yellow background. This version was also painted by Nappi.