Margaret Peterson Haddix

Follows fifth grader Max as he searches for his best friend who disappeared, leaving behind a strange note.

Eleven-year-old Marin and her neighbor Charley hope that by preventing a disaster that occurred twenty years ago, they can save Charley's dad from a future of guilt and self-destructive behavior.

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,...

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.

Time-travelers Jonah and Katherine are summoned to help another missing child from history, this time Virginia Dare from the Roanoke Colony, but their journey is sabotaged and goes dangerously awry, leaving them in the wrong time period. Includes author's note about the history of Roanoke Colony and Virginia Dare.

Thirteen-year-old Bethany's parents have always been overprotective, but when they suddenly drop out of sight with no explanation, leaving her with an aunt she never knew existed, Bethany uncovers shocking secrets that make her question everything she thought she knew about herself and her family.

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

Time travelers Jonah and Katherine arrive in 1611 to rescue missing child John Hudson, son of the explorer Henry Hudson, but just as the mutiny on the Discovery is supposed to start, Jonah and Katherine's knowledge of history is tested once again, and they fear that more is at stake than just one boy's life. Author's note includes facts about Henry Hudson's explorations.

Jonah, thirteen, and Katherine, eleven, travel through time to 1918 Russia just as Alexei, Anastasia, and the rest of Tsar Nicholas II's family is about to be executed. Author's note includes facts about the Romanov's and the mystery surrounding their deaths.

Fourteen-year-old Avery Armisted and sixteen-year-old Kayla Butts, once good friends, begrudgingly travel to Spain together for a summer vacation where they uncover a secret their families kept hidden from them their entire lives.