Scholastic broke new ground when it corralled a stable of boldface names to author The 39 Clues – a multi-platform series involving books, collectible cards, and an online game – which launched with Rick Riordan’s The Maze of Bones in fall 2008. Gordon Korman, Jude Watson, Patrick Carman, and Linda Sue Park were among the other contributors to the original 11-book series, which led into The 39 Clues: Cahills vs. Vespers. The final novel in that six-volume series, David Baldacci’s Day of Doom, whose newly revealed cover appears here, is due March 5. And 2013 will also bring the debut book of a new, four-installment story arc, The 39 Clues: Unstoppable, which starts in the fall with a still untitled novel by Watson. Jeff Hirsch, Natalie Standiford, and Korman will pen the third series’ subsequent installments.

The numbers attached to The 39 Clues brand back up Watson’s assertion that the series’ original premise – two siblings from an influential family are on a quest to find the formula for a serum that can create the most powerful person on earth – is “magic in a bottle.” Foreign rights to The 39 Clues have been sold into 27 countries, the books have more than 15 million copies in print worldwide, and the online game has more than two million players registered and continues to attract approximately 1,300 new users each day.

Asked about the impetus behind Unstoppable, Scholastic executive Rachel Griffiths, who manages the editorial work on The 39 Clues, has a ready answer: “It was the kids – it’s always the kids. They were clamoring for more.” The August 2011 installation of the Cahill Command Message Board on The 39 Clues Web site opened wide the communication lines between the publisher, the series’ authors, and readers. “Kids are posting all the time – on average, we receive 1,000 messages a day,” Griffiths says. “They told us that they were sad that Cahills vs. Vespers was winding down, and were desperate for new stories. When they ask for something, we always like to be there for them. And the kids really pushed for this.”

There are several forces driving The 39 Clues’s popularity, adds Stacy Lellos, v-p of marketing and multiplatform publishing. “One is the storyline, of course. And the multi-platform piece is important, too. Kids can have a great online experience, now available as an app, and their response to that has been unbelievable. With the message board, fans have the ability to post their own writing, engage in dialogue with kids from around the world, and interact with the authors themselves, which is very exciting for them. This gives them a really personal connection to the stories.”

Skippering the Latest Venture

Veteran 39 Clues author Watson handed in the manuscript for the inaugural Unstoppable book just this week. The pseudonymous author (who as Judy Blundell wrote the National Book Award-winning What I Saw and How I Lied) also created the overall story arc for Unstoppable, as she did for Cahills vs. Vespers. The new storyline sends protagonists Amy and Dan Cahill on even further-flung adventures as they explore the lost civilizations of the world. After she and Scholastic editors (including v-p, publisher, and editorial director David Levithan, who is at the publishing helm of The 39 Clues) firmed up the new arc’s premise, Watson went to work fleshing it out.

“I sat down with this big pad and a whole bunch of colored Sharpies and threw down ideas as fast as I could think of them,” she explains. “I beat my brains out against the wall and somehow things fell into place. With The 39 Clues there is so much already there for me to work with. We’ve set up this great group of characters kids really want to follow, and the narrative framework is already there – with great possibilities for adventure and danger.”

Writing Unstoppable’s debut novel entailed a significant amount of research on Watson’s part. “The research is the fun part – I get to be an armchair traveler,” she says. “For this story, I researched ancient Troy, The Iliad, and other meaty stuff that I know kids want.” And there were also the persnickety details. “Part of the plot takes place in Turkey,” she explains, “So I had to find out what people eat for breakfast in Turkey.”

Watson finds The 39 Clues’s collaborative process rewarding – and smooth going. “Of course, when I develop an arc, I’m involved to a certain degree with authors’ questions about the arc,” she says. “But the great thing about The 39 Clues is that Scholastic sets up each author with a blueprint, leaving lots of wiggle room. We’re working with some of the greatest adventure novelists in the business – certainly no one is going to tell Gordon Korman how to write an escape scene! Where we really all collaborate is when we go out on school visits together and talk about the books.”

School and bookstore visits have, in fact, provided Watson with some very satisfying moments. “The online component of the series is great because the Web can act as a gateway for kids who don’t usually read,” she says. “When I get to bookstore events early, there’s usually a kid or two already there, and they’ll come up shyly and ask me to sign their books. And often their parents will come over and say, ‘I want to thank you. My child didn’t read before finding these books.’ That is so very gratifying, and a really amazing part of the 39 Clues experience – for all of us.”