The Clue of the Black Keys is the twenty-eighth volume in the Nancy Drew mystery series. It was first published in 1951 under the pseudonym Carolyn Keene. The actual authors were ghostwriters Wilhelmina Rankin and Harriet Stratemeyer Adams.

Summary (original edition)

In The Clue of the Black Keys, a cryptic set of ancient keys unlocks a dangerous archaeological mystery in this exotic adventure that sends Nancy Drew from American university halls to the sunbaked ruins of Mexico. The story begins when young archaeology professor Terry Scott enlists Nancy’s help after being robbed of three black keys—artifacts believed to reveal the location of a lost Mayan treasure.

The investigation heats up as Nancy discovers rival scholars will stop at nothing to claim the discovery. Her search takes her through campus laboratories where the keys’ strange metallic composition is analyzed, to musty antique shops hiding coded maps, and finally to Mexico’s Yucatán peninsula. There, amidst crumbling temples and dense jungle, Nancy deciphers hieroglyphic clues while evading booby-trapped ruins and a criminal gang disguising their activities as archaeological digs.

Danger lurks in every shadow—Nancy narrowly escapes a collapsing tunnel, outwits armed pursuers in a moonlit temple courtyard, and ultimately confronts the mastermind in a dramatic showdown at a sacred cenote. The 1951 original edition pulses with postwar fascination for Mesoamerican cultures while delivering one of Nancy’s most globe-trotting cases. Unlike later revisions, this version retains thrilling sequences of actual artifact handling now considered culturally insensitive, reflecting changing attitudes toward archaeological practices.

The novel stands out for its authentic 1950s academic setting and vivid Mexican landscapes, showcasing Nancy’s adaptability across cultures. Her ability to interpret ancient symbols while navigating very modern dangers makes this one of her most intellectually demanding cases—proving that some treasures hold more than monetary value, they hold historical truths worth protecting.

Nancy Drew #28 –The Clue of the Black Keys First Edition Book Identification

Only the first few printings of the first/second year are shown. Printings codes are based on the Farrah Guide, 12th printing. Please refer to the guide for later printings.

Nancy Drew #28 –The Clue of the Black Keys First Edition Dust Jacket Identification

Reference:

• Farah’s Guide to Nancy Drew, 12th printing