Fifteen years after the collapse of the Berlin Wall signaled the end of communism and—gasp!—threatened to put secret agents out of business, swarms of young spies of all sizes, sexes, even species, are poised for an invasion.

"Just because the Cold War ended and John le Carré had to find new things to write about, the genre didn't go away," said Michael Green, associate publisher at Philomel Books and editor of Anthony Horowitz's Alex Rider series, which kicked off the trend with Stormbreaker in 2001.

Alex now not only has to contend with his own enemies but with competition. He'll soon have on his heels curvaceous-babe spies, child spies, spy mice, pet sleuths and—potentially the biggest rival of all—a teenage James Bond. SilverFin by Charlie Higson, the first in a series of prequels commissioned by Ian Fleming's estate, which debuts in April from Miramax/Hyperion.

But other publishers aren't all that worried about the competition. "Young Bond will actually help us," said Rick Richter, president and publisher of Simon & Schuster children's book division, "by bringing attention to the genre." He has to hope so. S&S will unveil three separate spy series this year: Spy Mice by Heather Vogel Frederick; Mission Spy Force by Deborah Abela; and a British import, Cherub, a six-book series about child spies that Hodder has published in the U.K.

Atheneum will also publish a stand-alone novel, Secret Agent by Robyn Freedman Spizman and Mark Johnston, and Simon Spotlight plans tie-in books and merchandise spin-offs from Totally Spies!—an animated Cartoon Network offering about three Beverly Hills High teens who do their surveillance between pre-calculus and trips to the mall. At Scholastic, an original paperback series, Spy X by Peter Lerangis, follows the exploits of twins Andrew and Evie as they search for their missing mother.

Richter thinks there's room in the tent for all, crediting the Spy Kids movie franchise with reviving interest in moles, gadgets and code names. "Spy Kids definitely kicked it off," he said, "and these trends often come in waves. There's also no doubt that the Harry Potter effect gives a bounce to everything that fantasy readers might like."

The spy who has made the biggest name for herself in children's books, of course, is Harriet M. Welsch, who for 30-plus years has been leading girls to record their observations in secret notebooks. But Harriet may soon have to share billing as top youth sleuth with a British teen named Alex Rider.

Booksellers say there are plenty of fantasy readers who are drawn to subterfuge and high-tech gadgetry, but these days they are almost exclusively middle-grade boys, and the books they've been buying in big numbers star British author Horowitz's teen sleuth. Puffin's paperback sales for the first four Alex Rider books have topped 300,000 copies, with the first title, Stormbreaker, accounting for nearly half those purchases.

"For Christmas, the series was very strong," said Joan Trygg, a bookseller at Red Balloon Bookshop in St. Paul. Minn. "I tried the books out with my son [now 14], because he reads a lot of fantasy, and they passed his test. He really likes them."

Philomel has ordered a first hardcover printing of 75,000 for the fifth Alex Rider installment, Scorpia. That new title will ship in March and will include nine scorpion skateboard decals as a gift with purchase. This fall, Alex will get his first boxed set and his first ancillary product—The Alex Rider Gadget Book.

"The new books go instantly to No. 1 in the U.K.," Green said. "We are a slower build, but we are a definite build."

Green had edited Horowitz's novel The Devil and His Boy (Philomel, 2000), and the two became fast friends. "It wound up being a great experience and there was no breaking the bond at that point, if you'll pardon the pun." After reading the manuscript for Stormbreaker, he immediately wanted more.

"The 12-year-old boy in me was just hopping up and down," Green recalled. "I offered a two-book contract even though there was no promise of a second book." Film rights have since been sold, and Kenneth Branagh is attached to direct.

Little, Brown caught the trend early, too, with Spy High, a six-book series by A.J. Butcher, which debuted in May 2004. The series follows a group of kids at a futuristic high school, where the curriculum includes martial arts, computer hacking and How to Defeat Megalomaniacs. The fifth in the six-book series, Blood Relations, releases in April. Sales have been strong, said editor Jennifer Hunt, who inherited the series on her first day on the job.

"We did get a huge buy from the [book] clubs," Hunt said, "which really helps because you're competing with so many other titles and that's a way to reach a big audience at once. But with this kind of book, I think you actually need less of a hook because kids already know how exciting it is. Each generation still gets excited about James Bond."

Ah, Bond. James Bond. Will he overshadow the rest of the field? Hyperion, whose Spy Kids tie-ins sold more than 1.1 million copies, acquired the rights to two Young Bond books at auction. Higson, a British actor and writer who specializes in comedy, had never written for the youth market before, but Hyperion executive editor Alessandra Balzer praises the author's depth. "It shows us how James got the skills he has an adult—why is he such a great athlete? You see him training at Eton. How does he stay so calm? That's part of his history, too."

Booksellers are already predicting that Young Bond will be a big hit with the same crowd that can't get enough of Alex Rider. "I groaned because I think you have to have a Y chromosome to enjoy them, but I bought them," said Donna Gerardo, children's book buyer at Books Etc. in Falmouth, Me. "I do think they'll be really popular with boys." Miramax plans a 150,000-copy first printing of SilverFin, with a $200,000 marketing campaign.

Part of the appeal of the spy genre, everyone agrees, is not only the nonstop action and the high-tech tools, but the derring-do spy heroes are often called upon to demonstrate. "The reader gets to be the superhero in charge," Gerardo said. Green agreed: "All fantasy is escapism, but spy fantasies are empowering."

That said, Alex Rider's latest adventure had readers buzzing last fall, when advance galleys began to circulate. Scorpia ends with Alex getting shot, left for dead on the sidewalk. Could this particular spy have met his match?

"Well, I don't want to give a thing away," Green said. "But I will say I just finished editing book six."