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,...

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

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

In a future world of false identities, government lies, and death threats, Luke feels drawn to the younger brother of the boy whose name Luke has taken.

Jonah, Katherine, Chip, and Alex suddenly find themselves in 1483 at the Towerof 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.

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.