Margaret Peterson Haddix

The Greystone kids thought they knew. Chess has always been the protector over his younger siblings, Emma loves math, and Finn does what Finn does best--acting silly and being adored. They've been a happy family, just the three of them and their mom. But everything changes when reports of three kidnapped children reach the Greystone kids, and they're shocked by the startling similarities between themselves and these complete strangers. The other kids...

Throughout the hunt for the 39 Clues, Amy and Dan Cahill have uncovered history's greatest mysteries and their family's deadliest secrets. But are they ready to face the truth about the Cahills and the key to their unmatched power? After a whirlwind race that's taken them across five continents, Amy and Dan face the most the difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

One minute the teens are there playing and laughing, the next they have disappeared from the lawn at the house next door, and Marin cannot believe it. When she meets Charley she discovers she is not the only one who has seen the teens, and Charley calls them the "Remarkables." Charley warns Marin not to approach them, but Marin can't stop thinking about something that happened back in her old house, and wondering if the Remarkables could help her--or...

When thirteen-year-olds Jonah and Chip, who are both adopted, learn they were discovered on a plane that appeared out of nowhere, full of babies with no adults on board, they realize that they have uncovered a mystery involving time travel and two opposing forces, each trying to repair the fabric of time.

"When Colin finds a shoebox full of letters hidden in a stranger's attic, he knows he's supposed to throw them away. That's his summer job, getting rid of junk. But Colin wants to rescue the letters--and find out what really happened to best friends Rosemary and Toby way back in the 1970s. Meanwhile, across town, Nevaeh also finds a mysterious letter. But this one reads like a confession to a crime. And Nevaeh knows her father, the 'Junk King,' expects...

In a society that allows families to have only two children, a group of third-borns tries to save themselves and others like them.

Jonah, Katherine, Chip, and Alex suddenly find themselves in 1483 at the Tower of London, where they discover that Chip and Alex are Prince Edward V and Richard of Shrewsbury, imprisoned by their uncle, King Richard III, but trying to repair history without knowing what is supposed to happen proves challenging. Author's note includes historical facts about the princes and king.

In a society that allows families to have only two children, third child Matthias joins the Population Police to infiltrate their system.

"Colin and Nevaeh are great at finding things. After all, they found each other and became best friends -- even though their parents are business rivals. They also found hidden boxes of secret letters, which led them to unravel mysteries about kids from the 1970s. But when they started Mystery Solvers Inc., they didn't expect to be asked to find a ghost. Ree recruits them to investigate a series of old, spooky photos left behind in her family's new...

When Jonah and Katherine travel to early 1900s Switzerland and Serbia to return Albert Einstein's daughter, Lieserl, to history, her mother Mileva grasps entirely too much about time travel and has no intention of letting her daughter go.