The 39 Clues is a 14-book series with 11 released primary works first released in 2008 with contributions by Rick Riordan, Gordon Korman, Peter Lerangis, Jude Watson, Patrick Carman, Linda Sue Park, Margaret Peterson Haddix, Mallory Kass, Scholastic Inc., and Clifford Riley.
The 39 Clues series is a thrilling adventure following siblings Amy and Dan Cahill as they race against ruthless relatives to find 39 hidden clues, scattered globally, that reveal the secret to their family's immense power, forcing them to uncover historical mysteries while battling dangerous family members and making choices that impact world history