"Could the Mark Twain books hidden through Book Scavenger contain clues about the string of recent arson fires plaguing the city? And will Emily and James uncover the mystery before the arsonist comes after them?"--

Thirteen-year-old Ruby, a genius code-cracker and daring detective, gets an anonymous call setting a challenge that leads her to the headquarters of Spectrum, a highly secret anti-crime agency that needs her help to crack a code, but soon Ruby uncovers dastardly plans of the Fool's Gold Gang.

The end is near! Book 9 of the #1 NY Times Bestselling series.

The shadow of a man in black has followed fourteen-year-old Amy Cahill and her younger brother, Dan, on their worldwide search for 39 Clues that lead to a great power. Amy and Dan know the man in black has tried to kill them. They know he's a Madrigal, the most secretive and terrifying group hunting for the Clues. Amy and Dan have run hard and fast, but they can't escape the man...

657 days ago Meg's British father left their home in France to fight the Nazis, leaving some codes in a jar for her to decipher, and Meg and her French mother moved to the Perche, a region in France near Normandy known for its forests; now Meg watches the German soldiers in town, and sometimes carries messages for the French resistance--but suddenly things have gotten much more dangerous: there is a wounded British officer hiding in her grandmother's...

Could Amy and Dan's biggest enemy be . . . a friend? Book 6 in the bestselling The 39 Clues series challenges everything you thought you knew about the Clue race.

Fourteen-year-old Amy Cahill and her younger brother, Dan, head to the Land Down Under to discover what their own mother and father knew about the hunt for the 39 Clues. But following in their parents' footsteps brings up lost memories for Amy so awful that she can't share them . ....

During World War II, eleven-year-old Felicity is sent from London to Bottlebay, Maine, to live with her grandmother, aunt, uncle, and a reclusive boy who helps her decode mysterious letters that contain the truth about her missing parents.

For 500 years, the Cahills have been the most powerful family in the world. For 500 years, they've protected the source of their power - the 39 Clues. And for 500 years, they've kept their secrets silent. Until now.This extraordinary stand-alone novel cracks open the Cahill vault to tell the story of the most coveted piece of artwork in the world, a masterpiece that has been the target of seven separate theft attempts: Jan van Eyck's altarpiece

...

On an island nation in the Indian Ocean, the explorers venture through a vast underwater world and take part in a friendly robotics competition. But the tides of good fortune change quickly. Suddenly, Team Cousteau jumps into action to rescue a faculty member from the brink of death. Meanwhile, the team follows the Cruz's mother's clues to a magnificent tomb and center of spirituality precariously perched on the side of a cliff. There, Cruz is confronted...

Told in multiple voices, fifteen-year-old Jamaican Louisa Adair uncovers an Enigma machine in the small Scottish village where she cares for an elderly German woman, and helps solve a puzzle that could turn the tide of World War II.