The 39 Clues
|Media type||Print (hardcover)|
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, and Natalie Standiford. The books chronicle the adventures of two siblings, Amy and Dan Cahill, who discover that their family, the Cahills, has been the most influential family in history. The main story arc concerns Dan and Amy's quest to find the 39 Clues, which are ingredients to a serum that can create the most powerful person on Earth. This series is generally for ages 9-12.  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. As of July 2010[update], the book series has about 8.5 million copies in print and has been translated into 24 languages. The major publisher of the books is Scholastic Press in the United States. Steven Spielberg acquired film rights to the series in June 2008, and a film based on the books will be released in 2016. The series also originated tie-in merchandise, including collectible cards and an interactive Internet game.
- 1 Series One: The 39 Clues
- 1.1 Book 1: The Maze of Bones
- 1.2 Book 2: One False Note
- 1.3 Book 3: The Sword Thief
- 1.4 Book 4: Beyond the Grave
- 1.5 Book 5: The Black Circle
- 1.6 Book 6: In Too Deep
- 1.7 Book 7: The Viper's Nest
- 1.8 Book 8: The Emperor's Code
- 1.9 Book 9: Storm Warning
- 1.10 Book 10: Into The Gauntlet
- 1.11 Book 11: Vespers Rising
- 2 Series Two: Cahills vs. Vespers
- 3 Series Three: Unstoppable
- 4 Series Four: Doublecross
- 5 Characters
- 6 Supplementary works
- 7 Cards
- 8 Themes
- 9 Origins
- 10 Reception
- 11 Film
- 12 See also
- 13 References
- 14 External links
Series One: The 39 Clues
The novels revolve around Amy and Dan Cahill, orphans who, upon their grandmother's death, discover that they are members of the Cahill family, whose members have shaped world history. The ancestors of the family are Gideon and Olivia Cahill, whose children created the branches of the family. The branches compete against each other in a hunt for the 39 Clues, ingredients to a serum, the source of the family's power. As Amy and Dan participate in the hunt, they unearth secrets about their Cahill ancestors, their parents, and the Madrigals, a mysterious organization.
Each book chronicles one location to which Amy, Dan, and Nellie travel and focuses on one historical character with whom a Clue has a link. The main narrative focuses on Amy and Dan's pursuit of the Clues while evading the sabotage of their competitors: Cahills from other branches. The books also contain the perspectives of the other Cahills as their views of Amy and Dan change. The environment all of the authors have created is an alternative reality in which influential historical figures belong to a single family. The world of The 39 Clues exists in parallel with the real world; other than the Cahills, no one knows that the Cahills exist or how much they have shaped the world.
Book 1: The Maze of Bones
Released September 9, 2008, The Maze of Bones is the first book in the series, written by Rick Riordan. Shortly before her death, Grace Cahill requests that her lawyer, William McIntyre, change her will. At the funeral, McIntyre informs her grandchildren, Dan and Amy, of a choice: one million dollars or a chance to be the greatest Cahill in history and the most powerful people in the world.
Amy and Dan enter the Clue hunt, competing against more experienced Clue hunters: the athletic Holts, brilliant Alistair Oh, the genius Starlings, the cunning and deadly Kabras, famous Jonah Wizard, and hardcore Irina Spasky. Pursuing clues hidden in Grace's library and in the Franklin Institute, Dan and Amy discover that Benjamin Franklin has hidden a clue in Paris. After convincing their au pair, Nellie, to chaperone their trip, Amy and Dan travel to Paris. Racing through Paris, the siblings solve codes and ciphers and find the clue in a vial. The Kabras steal the vial, but Dan solves the puzzle and discovers the clue: "iron solute". Amy's Internet searches for Franklin lead them to the probable location of the second Clue: Vienna, Austria, the home of Wolfgang Amadeus Mozart.
Book 2: One False Note
One False Note is the second book in the series, written by Gordon Korman and released December 2, 2008. After Amy, Dan, and Nellie obtain the first clue, they and the other Cahills travel to Vienna, Austria, to find a clue relating to Mozart and his sister, Maria Anna "Nannerl" Mozart. The Holts rob Amy, Dan, and Nellie of sheet music, a code that leads to the Clue, forcing them to rely on Dan's photographic memory. They go to an archive to find Nannerl's diary, only to discover that it has been stolen. They track down the thief, fellow competitor Jonah Wizard, and steal the diary back. The diary leads them to Salzburg, Mozart's birthplace; their search there ends in an explosion. Dan, Amy, and Nellie then go to Venice, where Dan and Amy sneak into a museum. The Kabras attack them and play the harpischord, triggering a booby trap that knocks them out. Amy and Dan find the second clue, tungsten, and a pair of Japanese swords, a hint for their next destination.
Book 3: The Sword Thief
The Sword Thief is the third book in the series, written by Peter Lerangis and released March 3, 2009. A pair of swords from Vienna leads Amy, Dan, and Nellie to Japan for a clue related to the Japanese warrior Toyotomi Hideyoshi. Teaming up with Alistair Oh and the Kabras, the three follow a trail of clues to Korea, where they stay at Alistair's house. A book in Alistair's secret library leads them to a mountain called Pukhansan. The group finds an entrance to a cave that hides Hideyoshi's treasure, and the third clue, gold. Dan decodes an anagram and tricks the Kabras, who escape and seal everyone else in the cave. After escaping, Dan, Amy, and Nellie head for Egypt, as hinted in the anagram.
Book 4: Beyond the Grave
Beyond the Grave is the fourth book in the series, written by Jude Watson and released June 2, 2009. Dan, Amy, and Nellie search for a clue in Egypt while being pursued by the other Cahills. They arrive in the Hotel Excelsior, an Ekaterina stronghold built by Bae Oh. Theo Cotter, an Egyptian archaeologist, aids them in their quest for the fourth clue. He betrays them, and the siblings and Nellie narrowly escape death. Grace had left them her old guidebook, a postcard which she sent to her friend Hilary Cotter (Theo's grandmother) and the priceless Sakhet statue, which was believed to be left by Katherine Cahill. Bae Oh finds them in the hotel's stronghold and traps them in an exhibit "To be seen by future descendants of Katherine". They find the fourth clue, half a gram of myrrh, through the Sakhet statue Grace left them. They barely escape Bae Oh with Nellie and Saladin's help. Jonah Wizard later traps them in a deserted island on the Nile. Some local fisherman save them and they decide to return to Egypt.
Book 5: The Black Circle
The Black Circle is the fifth book in the series, written by Patrick Carman and released August 11, 2009. After receiving a telegram from "NRR," a mysterious figure, Dan and Amy leave for Russia. Upon their arrival, another hint from NRR leads them to a credit card and false passports belonging to their dead parents. According to NRR, she is Nataliya Ruslanova Radova, the daughter of the last Romanov, which was a Lucian. She was not killed and escaped to live with a low profile. Suffering from a blood disorder, she was not able to join the clue hunt. Allying with the Holts, Amy and Dan infiltrate a Lucian stronghold. It reveals the next clue, amber.
Book 6: In Too Deep
In Too Deep is the sixth book in the series, written by Jude Watson, who wrote Beyond the Grave. It was released on November 3, 2009. Dan and Amy head to Sydney, Australia, to learn about what their parents knew about the 39 Clues from their dad's cousin, Shepard Trent. They discover that Ian and Natalie's mother, Isabel Kabra, has joined the hunt. Isabel hunts the two down to kill them, but the siblings escape and follow a clue to Krakatau (the ring of fire), where they meet Alistair. Isabel sets fire to their hut. Irina Spasky dies while saving Amy, Dan and Alistair. After the fire, the three look in Irina's bag and find song lyrics revealing the clue, water. At the end of the book, they suspect that Nellie spies on them for someone else.
Book 7: The Viper's Nest
The Viper's Nest is the seventh book in the series, written by Peter Lerangis and released on February 2, 2010. The morning after the fire that killed Irina Spasky, Dan and Amy discover that Irina's last words are a song, which points them to their next destination: Pretoria, South Africa. They infiltrate a Tomas stronghold, and the Holts chase them. As Dan and Amy leave South Africa, the Kabras capture them. Flying Grace's old plane The Flying Lemur, the siblings escape with a vial of green liquid. During a quarrel, the vial breaks, and the green liquid, a Kabra poison, spills onto Dan's arm. To save Dan, they fly to Grace Cahill's home in Madagascar, where they find out that the clue is aloe and their parents were Madrigals, an organization Amy and Dan have learned to fear, meaning that they themselves are Madrigals.
Book 8: The Emperor's Code
The Emperor's Code is the eighth book in the series, written by Gordon Korman. It was released April 6, 2010 Amy and Dan go to China to find the next clue. They split up following an argument but reunite at Mount Everest, where they find a Janus vial left by British Cahill mountaineer, George Mallory. They battle Eisenhower Holt and Ian Kabra over the serum. Ian falls, and Amy sacrifices the Janus serum to save Ian.
When Dan thinks they have lost the clue, Amy shows him the poem on the silk fabric they found in Beijing and tells him the next clue is raw silkworm secretion. They realize that a formula on the silk means that all the serum of the branches add up to one master serum. Dan shows Amy the locket he found at a Shaolin temple, which contains an inscription of the name of the pirate Anne Bonnie. They decide their next destination is the Caribbean.
Book 9: Storm Warning
Storm Warning, by Linda Sue Park, was released on May 25, 2010. Amy and Dan continue their hunt in the Bahamas and Jamaica. They distrust Nellie after discovering that she works for William McIntyre. After that, they head out to the Port Royal excavation site with Lester, Miss Alice's grandson, and find a box Grace donated that can fit the objects they collected. They cannot open the box, and after a non-Cahill ally dies, the siblings decide to quit the hunt. However, instead of driving them to the airport, Nellie stops at Moore town and gives the box to a mysterious man who has been following Dan and Amy. The man gives the siblings one hour to open the box. They figure out that on the strip they found is an unfolded möbius strip. Amy inserts the strip to the final slit and the box springs open. It contains a poem by Madeleine Cahill and the clue of mace.
The mystery man reveals his true identity as Fiske Cahill, Amy and Dan's great-uncle and Grace's younger brother, and tells them about Madeleine Cahill and the Madrigal branch, as well as granting the two active Madrigal status. He then also gives Nellie Madrigal status even though she is not a Cahill. After reading the poem, Dan concludes that the siblings' next stop is England.
Book 10: Into The Gauntlet
Into The Gauntlet, the penultimate book in the first series, was released on August 31, 2010, and was written by Margaret Peterson Haddix. All the teams arrive at the home of the founder, Gideon Cahill, on an island. Isabel Kabra captures them and forces each of them to reveal their clues by threatening to kill their loved ones. Amy smashes the serum over Isabel's head, knocking her out. Amy and Dan are left with a list of everyone's clues, which each team gives them.
Book 11: Vespers Rising
Vespers Rising takes place between the first and second series. It was written by Rick Riordan, Peter Lerangis, Gordon Korman, and Jude Watson. The book was released on April 5, 2011, and has four plot lines. The first describes Gideon's discovery of the master serum and betrayal by his friend and the first Vesper, Damien Vesper. The second recounts Madeline Cahill's life and her attempt to reunite the Cahill family, protect her father's ring, and outwit Damien Vesper in acquiring it. The third tells of Grace's first mission to Casablanca, as she competes against Vesper agent General George S. Patton to retrieve Gideon's gold ring. The fourth describes Amy and Dan's retrieval of Gideon's ring that Grace bequeathed to Amy, while escaping from Casper Wyoming, a Vesper agent who is after it.
Series Two: Cahills vs. Vespers
|This section requires expansion. (March 2012)|
Book 1: The Medusa Plot
|Series||Cahills vs. Vespers|
|Published||August 30, 2011|
|Preceded by||Vespers Rising|
|Followed by||A King's Ransom|
The first book, The Medusa Plot, is written by Gordon Korman and was released on August 30, 2011. Two years after the Clue Hunt, all who succeeded in finding Gideon's serum recipe have united. The feud between the Cahill branches has ended, and the family unites to battle a new enemy: the Vespers, a secret organization led by Vesper One who have been the Cahills' enemies since the time of Gideon Cahill.
The book begins when Vespers kidnap seven Cahills. Three other Vespers try but fail to kidnap Dan and Amy, who return to the mansion and learn of the other kidnappings. A helicopter then flies over the mansion, leaving an unmarked phone behind. It contains a text sent by Vesper One ordering them to go to Florence or one of the hostages dies.
Sinead, McIntyre, and Ian, who has arrived from London, remain in the Cahill Command Center to research the Vespers, while Dan and Amy go to Florence, where a message tells them to steal Caravaggio's "Medusa" in the Uffizi gallery. Jonah Wizard and Hamilton Holt help them steal the picture, but when they give the painting to the Vespers, it is a fake. Vesper One sends them a video of Nellie getting shot in the shoulder.
Amy, Dan, Hamilton and Jonah discover that decades ago, a Mud Angel named Tobin stole the real painting. They steal the painting from him but lose the chargers for the unmarked phone while escaping. When Ian looks for info on the phone, he runs into Evan, who recognizes it as a DeOssie phone. Ian recognizes the value of Evan's knowledge and invites him to join the Command Center.
The siblings find Latin words on the back of the painting, prompting Dan to ask his friend, Atticus, for help. Atticus tells Dan to come to the Colosseum, where Dan finds out that the snakes in Caravaggio's Medusa are a map of the Colosseum, with the spot where two snakes bite each other as the "X". In the tunnels, they find DaVinci's Medusa shield, on which Caravaggio based his picture, and the original copy of Marco Polo's book, 'Il Millione (The Million), which the Vespers want.
Jonah, Hamilton, Ian, and Sinead find the DeOssie factory and sneak in, finding the phone chargers they need. On the way out, Hamilton triggers a trap, which blows up the factory.
Dan and Amy go to a circus to give Vesper One the real painting, but a circus acrobat steals it. Leaving the circus, Dan and Amy see the acrobat dying on the sidewalk. When they ask her whom she works for, she replies, "Bruciato", or burned, referring to Vesper One's burned arm. They receive another text message from Vesper One, telling them to go to Lucerne, Switzerland.
Book 2: A King's Ransom
|Series||Cahills vs. Vespers|
|Published||December 6, 2011|
|Preceded by||The Medusa Plot|
|Followed by||The Dead of Night|
A King's Ransom, written by Jude Watson, was released on December 6, 2011. Amy and Dan are in Santa Maria Novella train station in Florence when they come across a girl named Vanessa Mallory, who is Cheyenne Wyoming in disguise, and use her as a distraction to get into the train for Lucerne, Switzerland, where Vesper One is sending them for their next mission: find the De Virga world map. On the train, the siblings realize that they have been tricked, and an Interpol agent named Milos Vanek tries to hunt them down. They escape by hiding inside luggage bags and disembark at Enderberg.
They disguise themselves as rich heirs to enter an auction house in Lucerne, then sneak into the office and retrieve the de Virga Map archives written in German. Ian translates it, revealing that four people--Otto Hummer the professor, Jane Sperling the socialite, Marcel Maubert the art dealer, and Reginald Tawnley, the person who owned a private library--have something to do with the map.
Later, William McIntyre meets Amy and Dan, gives them a GPS wrist watch, and drops them off at a safe house in Basel. Sinead and Evan share the information about the four listed in the archives: Maubert and Tawnley died in war, Hummel worked in the Nazi party, and Jane was a Jew whom the Cahills believe tried to protect the de Virga map, which was owned by a Jewish family.
Dan gathers ingredients to create the Master Serum, which he intends to use as backup. Using the information the center gathered, Amy concludes that they have to search Neuschwanstein Castle.
After calling for backup, Jonah and Hamilton come to Munich on their way to the castle but accidentally pick up Cheyenne Wyoming, who nearly kills them. Amy and Dan find a black notebook owned by Sparrow, a.k.a. Jane Sperling, at the castle. Inside is a note that leads to the de Virga map.
Analysis comes from the Command Center about the notes: they are about a Johannes Kepler book that was recovered from the castle to the Library of Philosophy and Cosmology in Prague, Czech Republic. They head there to investigate the book but cannot do so without a reference.
After going to Sedlec Ossuary on a hunch from the Command Center, they discover a flash drive file about a Vesper One report and the initials AJT, Arthur Josiah Trent, carved on the wall, which shocks Dan because Arthur was their father. They then call Erasmus, who explains how Arthur was initiated into the Vespers but later cut off ties with them. Afterwards, Ian calls to tell Amy that a Lucian professor has agreed to help Dan and Amy enter the Library of Philosophy.
After going to the library, they bump into Jake and Atticus, who decide to help the siblings. Inside, Katja Mavel, the director of the library, gives them what they want. They find the map inside the book.
In Rome, a Vesper dressed like a waiter kills William, who leaves a secret message in his shoe before he dies.
Back in Prague, Amy and Dan tell Atticus what they are doing, and Atticus reveals his involvement as a Guardian. Dan connects Il Milione and the map to Samarkand, Uzbekistan - their next destination. Vesper One asks them to drop off the package at the Astronomical Tower, near the statue of Jan Hus. They do, but it goes wrong when Atticus follows them and is kidnapped.
Vesper One now knows Dan and Amy have been hiding Marco Polo's epilogue and explains that Atticus was the price of keeping it from him. Minutes later, another message is sent to Dan's phone, apparently from AJT.
Book 3: The Dead of Night
|Series||Cahills vs. Vespers|
|Published||March 6, 2012|
|Preceded by||A King's Ransom|
The third book, The Dead of Night, is written by Peter Lerangis and was released on March 6, 2012. The Vespers have Atticus Rosenbloom. Unless Dan and Amy comply with the Vespers' demands, Atticus will die. Vesper One asks Amy and Dan to find a stale orb, an anagram for astrolabe. They fly to Samarkand, Uzbekistan, to find the astrolabe. Atticus escapes, and Dan suspects that his father murdered William McIntyre and is Vesper One. Ian goes to New York, suspecting Isabel to be Vesper One, and Isabel manipulates him into staying by saying that the other Cahills are not his friends. The hostages are rumored to be in Argentina because of a lizard Nellie holds in a photo.
Dan has gathered seventeen ingredients of the thirty-nine for his own master serum. He has also been receiving texts from a Vesper claiming to be his father, so he texts back a question to confirm this and is shocked that the answer is correct. The book reveals Vesper 4 to be weatherman Sandy Bancroft.
Book 4: Shatterproof
|Series||Cahills vs. Vespers|
|Published||September 4, 2012|
|Preceded by||The Dead of Night|
|Followed by||Trust No One|
Shatterproof, written by Roland Smith, was released September 4, 2012. Amy and Dan must comply with Vesper One's demands to steal the Golden Jubilee diamond displayed at Berlin's Pergamon Museum to keep Vesper One from killing a Cahill. The Diamond is too well protected, and they escape from security. Vesper One reveals that they were merely a distraction, and he has the things he needs. He tells them to find the "Apology", a Roman article written by a soldier. Jonah, Hamilton, and Erasmus work on tracking down Luna Amato so she can tell them the reasons and people behind William McIntyre's murder. Luna kills Erasmus, but Jonah kills her. The hostages try to escape, but the Vespers stop them. Phoenix falls off a cliff but survives and gets away. Before they escape, Casper and Cheyenne inform Amy and Dan of Phoenix's supposed death. Vesper Three is revealed to be Sinead Starling, who frames Ian.
Book 5: Trust No One
|Author||Linda Sue Park|
|Series||Cahills vs. Vespers|
|Published||December 4, 2012|
|Followed by||Day of Doom|
Trust No One is by Linda Sue Park, the author of Storm Warning, and was released on December 4, 2012. The novel features Isabel and takes place in Brazil. Vesper One tells Amy and Dan to go to Yale and steal the Voynich Manuscript, Folio 74. Evan finds out that Sinead is Vesper Three. She blocks Evan's messages, but Amy finds out, and the two fight before Sinead flees.
Amy then apologizes to Ian, and they find that the folio is missing. After meeting Dave Speminer (a friend of the Rosenblooms' mother, Astrid), Atticus remember something that his mom said to him before dying: Missing Voynich with LaCher. Vesper One streams a video of Nellie, telling them of Alistair's death. They check Astrid Rosenbloom's e-mail for clues about the folio's location and find a coded email to Astrid which directs them to the Iguazu Falls in Brazil. During a capoeira performance, a capoeirista "accidentally" injures Atticus. At the Falls, a second attack occurs, and a blow dart coated with curare hits Dan, but a nearby doctor saves him from the poison. They realize Isabel Kabra orchestrated the attacks and that there will be one more.
A taxi driver takes them to Mabu Thermas Hotel and Spa and sees Dan's new wallpaper on his laptop, one of the "plumbing pictures" in the Voynich. At the spa, they meet LaCher Siffright, who has Folio 74. LaCher protects Atticus from the third attack: a man who throws a knife and a skewer at Atticus. They find the folio and realize that Archimedes plays a part in the Vespers' master plan. They suspect Isabel to be Vesper One and ask Hamilton and Jonah to find out more about Archimedes. Amy is tricked into giving Vesper One Gideon's ring, which Grace entrusted her with.
They find out the Vespers' master plan: The Vespers want to use the things they stole to build the Machina Fini Mundi, a doomsday device using electromagnets on subduction zones to create natural disasters. Traumatized, Amy hides in her own mind, blocking out the real world. Dan decides that the team should go to Attleboro. He believes that to combat a doomsday device, he needs the serum which he recently created, and he drinks an unknown liquid an Ekaterina scientist manufactures.
Book 6: Day of Doom
|Series||Cahills vs. Vespers|
|Published||March 5, 2013|
|Preceded by||Trust No One|
|Followed by||Nowhere to Run|
The final book is by David Baldacci and was released March 5, 2013. Continuing from the last chapter of Trust No One, Dan drinks the "serum" that he made with the help of an Ekaterina scientist, but Amy reveals that she replaced the real serum with a mixture of vegetables. Amy tells Dan that Isabel Kabra is Vesper Two, not Vesper One, and that she is flying to Washington, D.C.
Following a clue from Atticus' mother, Amy and Dan go to the National Museum of Natural History, which houses the largest collection of Lewis and Clark items. On the train, Vesper One sends them a video of the hostages. Atticus realizes that Ted is blinking Morse code and decodes the message: Riley McGrath is Vesper One. At the museum, they find out that Isabel wanted to see Lewis and Clark's compass. Dan sees numbers and letters scratched onto the back of the compass.
Evan and Ian receive a call from Phoenix from a motel in Washington state and head there with Hamilton and Jonah, whom Sandy, Casper, and Cheyenne follow. Disguised as a waitress, Cheyenne forces them into a van, taking them to the Rocky Mountains. Dan decides to take a train to the Cascade Mountain Range, where they believe the hostages and the Machina Fini Mundi are. Atticus grows suspicious of Dave and finds out that Dave Speminer is an anagram of Damien Vesper, the founder of the Vespers. Dan learns that Isabel had been posing as his father and sending the text messages. Isabel kidnaps Atticus, steals the serum in Dan's bag, and escapes. Amy discovers that Isabel modified the coordinates etched on the compass's reverse. The location of the hostages and the Machina Fini Mundi turns out to be on the Rocky Mountains.
The Vespers move the hostages from the Cascades to the Rockies. En route, the hostages break free and incapacitate Sandy, Casper, and Cheyenne and meet up with Amy, Dan, Atticus, and Jake. They find the Machina Fini Mundi and battle the Vespers. The Vespers fatally shoot Evan, while the device electrocutes Natalie.
Amy turns the Machina Fini Mundi into a giant electromagnet. When the Vespers come, the device disarms and electrocutes them. Sandy and Damien arrive and hand out stone weapons. Isabel, having drunk Dan's serum and seeking revenge for her children, arrives and tries to stop Damien from inserting the final piece. The device activates, but Isabel destroys it. Damien melts into the device, causing an explosion, which kills Damien and Isabel. In the aftermath, Amy, Sinead, and Dan discuss how they will return to their normal lives.
Series Three: Unstoppable
The third series, Unstoppable, was revealed in Publishers Weekly on October 25, 2012. Jude Watson wrote the story arc for this series. Nowhere to Run, the first book in the series, was released October 1, 2013. The 2nd book, Breakaway, was released January 28, 2014, in the US and February 1 worldwide. The third book, Countdown, was released on April 28, 2014, in the US and May 1, 2014, worldwide, while the fourth book, Flashpoint, was released August 26, 2014, in the US and September 1, 2014, worldwide.
Book 1: Nowhere to Run
|Published||October 1, 2013|
|Preceded by||Day of Doom|
J. Rutherford Pierce, a presidential candidate, attacks Amy and Dan and steals the serum from the safekeeper, Sammy Mourad, to use its power to conquer the entire world. Amy and Dan go to Troy and Zurich to find an ingredient for the antidote for the serum. Pierce kidnaps Sammy, a Lucian-Ekaterina Student who made the Serum with Dan in Trust No One, in order for him to be able to mass-produce the serum. Meanwhile, Amy and Dan find a notebook belonging to Olivia Cahill in Ireland. It shows the ingredients to the antidote of the serum, which are scattered all over the world. Nellie disguises herself as a chemist in order to be hired by Pierce and rescue Sammy from Trilon Labrotories. Amy and Dan find six whiskers of an Anatolian leopard as the first ingredient of the antidote.
Book 2: Breakaway
|Published||January 28, 2014|
|Preceded by||Nowhere to Run|
Dan and Amy face an enemy who has found a way to use the source of the Cahill family power against them. To stop him, Dan and Amy must find the antidote to the serum that the enemy took: Siliphium. The search will take them from one of the world's hottest regions in Tunisia to the frozen blast of the Arctic Circle. With the enemy closing in, Dan faces the one terror he never imagined - being betrayed by his sister.
Book 3: Countdown
|Published||April 29, 2014|
With Dan's life on the line, Amy does something that sends shockwaves through the Cahill world. Will she live long enough to regret it? Or will she die before then? Amy takes the serum fabricated by Sammy Mourad while she and Dan were hanging from a bridge in Tikal, Guatemala. 
Book 4: Flashpoint
|Published||August 26, 2014|
Sixteen-year-old Amy Cahill only has a few days to live. There’s a poison coursing through her, and her only chance is to collect ingredients for an antidote. Too bad the antidote ingredients are scattered around the world. The antidote is also the only thing capable of stopping J. Rutherford Pierce, who is on the brink of becoming the most powerful man in the world. Amy and Dan will do everything it takes to bring Pierce down, even if Amy must pay the ultimate price.
Series Four: Doublecross
On April 26, 2014, at the New Hampshire Worlds Collide event, it was announced that the 39 Clues would get a fourth and final series titled, Doublecross. There will be at least four books.
Book 1: Mission Titanic
|Published||February 24, 2015|
The Outcast was banished from the Cahill family, never mentioned again. For years, he’s been lurking, watching, recruiting, waiting for the chance for revenge. And now he strikes, with a diabolical plan. The Outcast recreates four of history’s most infamous disasters, and gives the Cahill kids just days to stop them. The kids smell something fishy but when there are innocent lives on the line, the worst thing of all is the Devestating Betrayel that is waiting to come for Amy, Dan and Nellie... 
Scholastic has expanded the 39 Clues universe with several books. In 2010 Scholastic published Agent Handbook, which explores the techniques that the clue hunters in the series use to find clues, and The Black Book of Buried Secrets, which provides more information about events in the series. In the last week of December 2011, the Scholastic editorial team released seven short stories as part of The 39 Clues: Rapid Fire e-book series.[dead link] The editorial team has also released "The Cahill Files", which includes Operation Trinity, Spymasters, and four e-books. As part of the multimedia interactive experience to promote the series, Scholastic includes six cards in each book of the 39 Clues series. Each card leads to one online clue, which readers can unlock by entering the code on the cards on their 39 Clues account online.
The 39 clues also uses collectible cards in order to expand readers' experience of the series. In the first series of books, The Clue Hunt, each book came with six game cards. These cards all shared the same code and once added online would unlock the clue in that book. Alongside the first series of books, Card Packs were sold. These card packs contained 16 random cards out of a total of roughly 50 that were not available in the books. The card packs were: Card Pack - for books 1, 2 and 3 Card Pack 2: Branch vs. Branch - for books 4, 5 and 6 Card Pack 3: Rise of the Madrigals - for books 7 and 8 Ultimate Card Pack - for books 9 and 10
In the second series each book again came with six cards. However, unlike the first series, the cards were needed to unlock the online missions. Cahills vs Vespers also had two card packs. These card packs all contained the same 16 game cards, which would unlock the online extreme missions. The card packs were: The Marco Polo Heist - released with book 1 The Magellan Heist - released with book 4
In the third series Unstoppable, each book contains six game cards. These cards unlock an extra game in their corresponding online missions.
Overall, the cards are a key part of the series. Players on the online website can only collect all the clues through the use of the cards, and in later series can only unlock the missions by having the cards. The cards in the first series often had puzzles and riddles to find out.
Additional cards have been released over the course of the series, and the cards are only virtual. A game involving the cards, Doublecross, was created by Scholastic in which players physically use their cards to battle their opponents.
The 39 Clues series consists of adventure novels; however, the novels also fall within the genre of historical fiction. The stories switch back and forth between different characters' points of view. Each novel focuses on one historical figure and geographical location as Dan and Amy explore a clue related to a prominent Cahill family member in an exotic location.
One theme of the series is the relationship between talent and success. Each branch of the Cahill family has specific talents in a certain area; for example, the Ekaterina branch specializes in inventions and technology. Amy and Dan's competitors' talents give them an advantage, yet Amy and Dan consistently are ahead in the hunt and are viewed as the main threats. Over the course of the books, Amy and Dan discover their own talents.
An editorial team in Scholastic came up with idea of an interactive series with online games and asked Rick Riordan to write the first book. Riordan agreed because he thought it was a good idea, and as a middle school teacher, he loved making history enjoyable for younger readers. The project was kept secret for about two years.
As of June 11, 2010, The 39 Clues series has been on the New York Times bestseller list of Children's Series books for 48 weeks. Books in the series have also appeared on the USA Today, Publishers Weekly, and Wall Street Journal bestseller lists.
Critical reception of the 39 Clues has been mostly positive. The first book was met with positive reviews and spawned optimism for the rest of the series. The books have been very popular among kids.
Steven Spielberg acquired film rights to the series in June 2008. Spielberg and Scholastic Media president Deborah Forte will produce the series, while Brett Ratner expressed interest in directing the first film. Screenwriter Jeff Nathanson was hired to write the script in September 2008. In May 2012, Shawn Levy, the director of the Night at the Museum movies, acquired the rights to direct the movie. The movie, The 39 Clues: The Movie, is set to be released in August 2016.[not in citations given] The movie rights were taken by Universal, in August 2013.
- Riordan, Rick (September 9, 2008). The Maze of Bones. Scholastic. p. 23. ISBN 978-0-545-06039-4. OCLC 192081902. "If you accept, you shall be given the first of thirty-nine clues. These clues will lead you to a secret, which, should you find it, will make you the most powerful, influential human beings on the planet."
- Lodge, Sally (July 22, 2010). "The Success and Grand Finale of The 39 Clues". Publishers Weekly. Retrieved April 29, 2012.
- "The 39 Clues (2014)". MovieWeb. Retrieved September 23, 2014.
- Yin, Maryann (September 23, 2010). "David Baldacci Joins Several Authors to Write the 2nd Wave of '39 Clues' series". GalleyCat. Retrieved February 11, 2011.
- Smith, Roland. "The 39 Clues Message Board: Book 4 Cover Reveal". Scholastic Inc. Retrieved February 24, 2012.
- Linda Sue Park (2012-07-12). "Book 5 Cover Reveal!". Scholastic, 39 Clues Message Board. Retrieved 2012-07-15.
- Sneak peek at Book 5 of Cahills vs. Vespers Linda Sue Park on Twitter. 2012-06-13. Retrieved 2012-07-15.
- Fuentes, Catherine (September 22, 2010). "'39 Clues' exclusive: New series from Scholastic will feature David Baldacci". Entertainment Weekly. Retrieved October 23, 2010.
- by (2013-12-04). "The 39 Clues: Unstoppable Book 3: Countdown by Natalie Standiford | 9780545521451 | Hardcover | Barnes & Noble". Barnesandnoble.com. Retrieved 2014-01-30.
- "TITLE AND COVER REVEALED FOR 39 CLUES: UNSTOPPABLE, BOOK 4 – FLASHPOINT". Retrieved September 23, 2014.
- "The 39 Clues Message Board". Retrieved September 23, 2014.
- "The 39 Clues: Doublecross: Book 1". Scholastic. Retrieved 29 August 2014.
- "The 39 Clues: Doublecross Book 1: Mission Titanic: Jude Watson: 9780545747813: Amazon.com: Books". Retrieved September 23, 2014.
- Jude Watson. "Mission Titanic (The 39 Clues: Doublecross, #1)". Goodreads. Retrieved September 23, 2014.
- "The 39 Clues Online Press Kit". Scholastic Media Room. Scholastic.
- Jordan, Tina (April 5, 2010). "'The 39 Clues': Exclusive on final two titles, covers!". Entertainment Weekly. Retrieved February 11, 2011.
- Minzesheimer, Bob (November 11, 2011). "Scholastic to publish '39 Clues'-inspired e-book stories". USA Today. Retrieved April 29, 2012.
- Sekeres, Diane Carver; Christopher Watson (June 4, 2011). "New Literacies and Multimediacy: The Immersive Universe of The 39 Clues". Children's Literature in Education 42 (3): 256–273. doi:10.1007/s10583-011-9133-4. Retrieved April 23, 2012.
- Culham, Ruth. "Decoding Writing with The 39 Clues". Scholastic. Retrieved April 29, 2012. "The 39 Clues story is narrated from several different characters’ points of view."
- Stockwell, Laura. "Curriculum Guide for The 39 Clues series". Retrieved 2010-06-09.
- "Rick Riordan Author of the Month Transcript". Scholastic. Retrieved April 29, 2012. "Scholastic came to me with the basic idea and I thought it sounded cool. I like history, puzzles, and games, so the 39 Clues seemed like a perfect thing to write."
- "Rick Riordan Interview". Scholastic. July 2008. Retrieved April 29, 2012.
- Staskiewicz, Keith (August 30, 2010). "'The 39 Clues' round-robin interview". Entertainment Weekly. Retrieved April 29, 2012.
- Karen W. (September 9, 2008). "Rick Riordan in the House! (Part 1)". Ink Splot 26. Retrieved April 29, 2012. "for two years, no one on the team was allowed to say anything about the project to anyone."
- "Children's Books". The New York Times. June 11, 2010. Retrieved June 13, 2010.
- Michael Fleming (June 24, 2008). "Steven Spielberg follows '39 Clues'". Variety. Retrieved September 3, 2008.
- Tatiana Siegel (September 2, 2008). "Jeff Nathanson to write '39 Clues'". Variety. Retrieved September 3, 2008.
- Trumbore, Dave (May 10, 2012). "Shawn Levy to Direct Adventure Novel Series Adaptation The 39 Clues for DreamWorks". Collider.com. Retrieved June 2, 2012.
- "The 39 Clues". Retrieved September 23, 2014.
- Eleanor Barkhorn (July 18, 2011). "The Next Harry Potters: Where Are They Now?". The Atlantic. Retrieved September 2, 2011.
- "Universal Could Take ‘The 39 Clues’ From Steven Spielberg and Dreamworks | /Film". Slashfilm.com. 2013-08-21. Retrieved 2014-01-30.
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