Here's a breakdown:
* Adventure: The book follows the Cahill siblings as they travel around the world, facing dangerous situations and uncovering clues.
* Mystery: The book centers around solving the mystery of the 39 Clues and the secrets of the Cahill family's past.
* Historical fiction: The book incorporates historical figures and events, such as the Medici family and the Renaissance.
* Fantasy: The book includes elements of magic and supernatural powers, such as the "Cahill bloodline" and the "39 Clues."
Therefore, while adventure fiction is the primary genre, the book also draws from other genres to create a compelling and engaging story.