James, Rhondell, Sharice, and Marcel are four inner-city students on a quest to build the world’s largest tetrahedron with their math teacher, Mr. Collins. If they succeed, maybe Rhondell will make new friends, Sharice’s foster mother may start to care, James will discover something he’s good at, and Marcel’s dad will finally see that there is more to life than barbecue. Maybe they’ll even end up in the Guinness Book of World Records!

"Are you a gifted child looking for special opportunities?" Dozens of children respond to this peculiar ad in the newspaper and are then put through a series of mind-bending tests, which readers take along with them. Only four children—two boys and two girls—succeed. Their challenge: to go on a secret mission that only the most intelligent and inventive children could complete. To accomplish it they will have to go undercover at the Learning Institute for the Very Enlightened, where the only rule is that there are no rules.

With the defeat of the Overtakers behind them, the five teenagers known as the Kingdom Keepers should be celebrating. By all accounts they saved Disneyland from certain destruction. Why then did their mentor leave one last puzzle for them to decipher? The Keepers must solve a puzzle of the past, or be crushed under an evil that makes the Overtakers seem like gentle souls.

When Kate Pierce-Keller’s grandmother gives her a strange blue medallion and speaks of time travel, sixteen-year-old Kate assumes the old woman is delusional. But it all becomes horrifyingly real when a murder in the past destroys the foundation of Kate’s present-day life. Suddenly, that medallion is the only thing protecting Kate from blinking out of existence. Kate learns that the 1893 killing is part of something much more sinister, and her genetic ability to time travel makes Kate the only one who can fix the future.

What would happen if you discovered that your family was one of the most powerful in human history? What if you were told that the source of the family's power was hidden around the world, in the form of 39 Clues? What if you were given a choice - take a million dollars and walk away...or get the first Clue? If you're Amy and Dan Cahill, you take the Clue - and begin a very dangerous race.

In Jasper Fforde's Great Britain, circa 1985, time travel is routine, cloning is a reality (dodos are the resurrected pet of choice), and literature is taken very, very seriously. England is a virtual police state where an aunt can get lost (literally) in a Wordsworth poem and forging Byronic verse is a punishable offense. All this is business as usual for Thursday Next, renowned Special Operative in literary detection.

Ellingham Academy is a famous private school in Vermont for the brightest thinkers, inventors, and artists. It was founded by Albert Ellingham, an early 20th century tycoon, who wanted to make a wonderful place full of riddles, twisting pathways, and gardens. "A place", he said, "where learning is a game." Shortly after the school opened, his wife and daughter were kidnapped. The only real clue was a mocking riddle listing methods of murder, signed with the frightening pseudonym "Truly, Devious".

Thirteen extremely valuable pieces of art have been stolen from one of the most secretive museums in the world. A Vermeer has vanished. A Manet is missing. And nobody has any idea where they and the other eleven artworks might be...or who might have stolen them. The Players - Calder, Petra, and Tommy - are no strangers to heists and puzzles. Now they've been matched with two new sleuths - Zoomy, a very small boy with very thick glasses, and Early, a girl who treasures words...

The first day at a new school is tough for any kid, but it's especially scary when you're going to a school for spies. Cammie Morgan has spent her whole life dreaming of becoming a Gallagher Girl, but she has no idea what she’ll face when she arrives at The Gallagher Academy for Exceptional Young Women. Secret passages? Check. Lab experiments that might make you lose your eyebrows (and other body parts)? Check. Classmates who are the smartest, strongest, most intimidating girls in the world? Double check.

Dane and Mandy, a popular magic act for 40 years, are tragically separated by a car wreck that claims Mandy’s life—or so everyone thinks. Even as Dane mourns and tries to rebuild his life without her, Mandy, supposedly dead, awakes in the present as the19-year-old she was in 1970.

It was 1798 when the Morningstarr twins arrived in New York with a vision for a magnificent city: towering skyscrapers, dazzling machines, and winding train lines, all running on technology no one had ever seen before. Fifty-seven years later, the enigmatic architects disappeared, leaving behind for the people of New York the Old York Cipher - a puzzle laid into the shining city they constructed, at the end of which was promised a treasure beyond all imagining.

Ever wonder who was the first kid to keep a wallet on a big chunky chain, or wear way-too-big pants on purpose? What about the mythical first guy who wore his baseball cap backwards? These are the Innovators, the people on the very cusp of cool. Seventeen-year-old Hunter Braque's job is finding them for the retail market.

Welcome to Echo Falls. Home of a thousand secrets, where Ingrid Levin-Hill, super sleuth, never knows what will happen next.

On a foggy night in Amsterdam, a man falls from a rooftop to the wet pavement below. It's Archibald McQuinn, the notorious cat burglar, and he's dying. As sirens wail in the distance, Archie manages to get out two last words to his young son, March: "Find jewels." But March learns that his father is not talking about hidden loot. He's talking about Jules, the twin sister March never knew he had. No sooner than the two find each other, they're picked up by the police and sent to the world's worst orphanage. It's not hard time, but it feels like it.

When Amanda travels east to Orlando on a hunch, she's met with the worst news possible. Kingdom Keeper Finn Whitman is missing. Calling on her own gift (she's telekinetic), her sister Jess' ability to dream the future, and their fellow Fairlie Mattie Weaver's unexplained ability to read minds through physical contact, the three gifted girls must navigate treachery, deception, and the stubborn, unwilling parents of the missing Keepers if they're to save their friends.