The 39 Clues is a series of adventure novels written by a collaboration of authors, including Rick Riordan, Gordon Korman, Peter Lerangis, Jude Watson, Patrick Carman, Linda Sue Park, Margaret Peterson Haddix, Roland Smith, David Baldacci, Jeff Hirsch, Natalie Standiford, C. Alexander London, Sarwat Chadda and Jenny Goebel. It consists of five series, The Clue Hunt, Cahills vs. Vespers, Unstoppable, Doublecross, and Superspecial. They chronicle the adventures of two siblings, Amy Cahill and Dan Cahill, who discover that they are a part of the most influential and powerful family in history.
The first arc follows Amy and Dan's quest to find the 39 clues, a secret that will make its discoverer the most powerful person in the world. Subsequent arcs chronicle Amy and Dan's conflicts with enemy parties who desire either the clues or other Cahill family secrets. This series' primary audience is ages 9–14. Since the release of the first novel, The Maze of Bones, on September 9, 2008, the books have gained popularity, positive reception, and commercial success. , the book series has about 8.5 million copies in print and has been translated into 24 languages.
The books are published by Scholastic Press in the United States. Steven Spielberg acquired film rights to the series in June 2008, and a film based on the books was set to be released in 2016, but, as of October 2025, production has not yet started. The series also originated tie-in merchandise, including collectible cards and an interactive internet game.
Characters
The books follow the adventures of Amy and Dan Cahill, two orphaned siblings from Massachusetts who become involved in the affairs of the Cahill family following the death of their grandmother, Grace Cahill. They are under the legal guardianship of their great-aunt Beatrice Cahill. Throughout their travels, they are assisted by their au pair Nellie Gomez and Grace's retainer William McIntyre.
Introduced in the first series as the competition are wealthy and ruthless English siblings Ian and Natalie Kabra, the athletic and militaristic Holt family—consisting of parents Eisenhower and Mary-Todd, son Hamilton, and twin daughters Reagan and Madison—hip-hop and action film celebrity Jonah Wizard and his manager/father Broderick, triplets academics Sinead, Ned, and Ted Starling, failed South Korean businessman Alistair Oh, and Russian ex-KGB assassin Irina Spasky. While Ian and Natalie's mother Isabel is the main antagonist, the mysterious presence of the Man In Black threatens the Cahill siblings at every turn.
In the second series, Amy and Dan are assisted by scholarly half-brothers Jake and Atticus Rosenbloom, Turkish spy Erasmus Yilmaz, and biochemistry graduate student Sammy Mourad. They encounter Interpol agent Luna Amato while Hamilton Holt is a fan of celebrity meteorologist Sandy Bancroft. While the Cahill's primary fight is with Vesper One, they also encounter his field agents, twin thieves Cheyenne and Casper Wyoming.
The third series sees the Cahills attempt to thwart media tycoon and aspiring politician J. Rutherford Pierce, whose children, Cara and Galt, work on his behalf. Nellie finds and enlists the help of digital cowboy Pony. In the fourth series, a usurper called the Outcast challengers the Cahills to prevent four disasters and demands they enlist no outside help.
Books The Clue Hunt
The first series follows orphans Amy and Dan Cahill who discover their family has shaped world history and includes almost every notable historical figure from the past five centuries. The family is divided into four branches—the artistic and creative Janus, the innovative and exploratory Ekaterina, the physically strong and determined Tomas, and the cunning and strategic Lucians. As part of their late grandmother's will, Amy and Dan engage in a competitive international hunt for the clues while evading various recurring Cahill relatives. Each book focuses on the search for a single clue and the historical figure who discovered it first.
The Maze of Bones
The Maze of Bones is the first book in the series, written by Rick Riordan and published on September 9, 2008. It is 220 pages long.
Minutes before her death, New England socialite Grace Cahill alters her will. At her funeral, her grandchildren, Amy and Dan Cahill, choose one of thirty-nine clues over a one million dollar inheritance; siblings Ian and Natalie Kabra, the Holt family, the Starling triplets, Jonah Wizard and his father Broderick, businessman Alistair Oh, and assassin Irina Spasky also choose the clue; a total of seven teams are formed. Amy and Dan also learn that their family is the most powerful in human history, having influenced every aspect of human culture and society over the past five centuries. Almost every notable historic and public figure has been a member of the family, which is divided into four branches—the Lucian, the Ekaterina, the Tomas, and the Janus; each branch has specific skills and attributes and all share a common enemy in the mysterious Madrigals. Amy and Dan are aided by Alistair Oh as they discover a connection to Benjamin Franklin, but become separated in a fire secretly set by the Holts. Amy and Dan see The Man In Black in the distance and fear him. The Starlings are hospitalized following an explosion also set by the Holts while Amy and Dan travel to Paris with the help of their au pair Nellie Gomez. After declining an alliance proposed by Jonah and narrowly surviving a trap set by Irina Spasky and the Kabras, Amy and Dan search the Paris catacombs and find a series of numbers that direct them to music composed by Wolfgang Amadeus Mozart. Soon after, they learn about the original Cahill siblings—Luke, Kathrine, Thomas, and Jane—and discover a vial of liquid requiring an electric charge. At a nearby church, the teams converge on Amy and Dan in search of the vial. Amy and Dan, being chased by the Holts, climb into the bell tower, and Amy uses the church's lightning rod to charge the vial; it is then immediately stolen by Ian Kabra who uses a kite to glide out of the tower. The following morning, Amy and Dan realize the clue is "iron solute", an anagram of "resolution" which was part of the original clue given at Grace's funeral. On the trail of Mozart, they prepare to travel to Vienna.
One False Note
One False Note, the second book in the series, was written by Gordon Korman and published on December 2, 2008. It is 174 pages long.
On the train to Vienna, the Holts attempt to steal the sheet music from Amy, Dan, and Nellie, but it is destroyed and the teams part ways. Dan reveals he memorized the music and writes it on a napkin. Arriving, Amy and Dan visit Mozart's childhood home-turned-museum and learn of a diary written by the composer's sister, Nannerl; it is revealed to have been stolen, and that night in their hotel, Amy and Dan conclude Jonah and Brodrick are the thieves. Breaking into Jonah's hotel room, Amy and Dan steal the diary back while Nellie is arrested but released later in the night. Irina attempts to steal the diary but is tricked by Dan while Amy quickly discovers that the diary is missing pages. Following what information they glean, the three travel to Salzburg and follow Alistair into a cave. The sight of a Man In Black forces them deeper into the cave and a small explosion traps them; they manage to escape but are pursued by Benedictines before reuniting with Nellie who has found a tracker under Saladin's collar. They plant it on a sleeping Alistair and steal his lead which points to Venice. Arriving by car, they follow Jonah's vehicle and eventually track him to a record shop which houses a secret entrance into a Janus stronghold. There, Amy and Dan find the missing diary pages but are discovered shortly after stealing them; they escape and a chase across the canals ensues. Amy and Dan eventually lose the Janus but are knocked into the canals by Ian and Natalie. Recovering, Amy and Dan are eventually able to get Nellie—fluent in German—to read the diary pages, which point to merchant Fidelio Racco who has a house-turned-museum in Venice. Amy and Dan sneak in after closing with the intent of playing the sheet music on Racco's harpsichord, but Ian and Natalie interrupt them. As Ian begins playing, Amy realizes an earlier clue from the diary pages warns that the instrument is rigged, but is unable to stop Ian from playing the sabotaged key and triggering an explosion that knocks him and Natalie out. Amy and Dan continue the piece and discover two tungsten katanas, informing them of their second clue and next destination, Tokyo.
The Sword Thief
The Sword Thief is the third book in the series. It was written by Peter Lerangis and published on March 3, 2009.
At Fiumicino airport, Amy and Dan are about to follow Nellie onto their Tokyo-bound commercial flight when Ian and Natalie Kabra, having infiltrated airline personnel, pose as Dan and Amy and take their place on board. Stranded, Amy and Dan are forced to join in alliance with Alistair, who takes them to Tokyo in exchange for learning Tokyo is their destination. Dan learns through computer research that Toyotomi Hideyoshi is their historical figure of interest but the three are kidnapped by the Holts and forced to share their lead. Searching the Tokyo subway tunnels, Amy, Dan, and Alistair become separated from the Holts but get chased by the Yakuza. Ian, Natalie, and Nellie arrive to rescue them and the six for an alliance. Amy and Dan share what they found with Alistair—seemingly random shapes, but combine with a coin provided by Ian, Alistair conclude they must continue their search in Seoul. After researching in Alistair's private library—where Amy and Dan learn that a fire tore the original Cahill family apart—the group sets their sights on Pukhansan where they find a secret entrance that they unlock using the coin. Amy, having developed a potential romance with Ian, gives him back the coin. After learning that the next clue is gold—a clue Alistair and the Kabras already know—and learning the next location is Lake Tash, Ian and Natalie betray the alliance and use the coin to lock the others in the cave. Alistair notices explosives hidden in the cave's ceiling and Dan uses matches acquired in Tokyo to light them up, creating an exit. Alistair fails to escape while Dan informs Amy that the real next location is Cairo and concerns Sakhet. Dan realizes Alistair is secretly alive while Alistair, having faked his death on purpose, threatens his murderous uncle, Bae.
Beyond the Grave
Beyond the Grave is the fourth book in the series. It was written by Jude Watson and published on June 2, 2009. It is 156 pages long.