The Battle of the Labyrinth
Rick Riordan
Percy Jackson and the Olympians (4)
The Last Olympian
Percy Jackson and the Olympians (5)
The Lightning Thief
Percy Jackson and the Olympians (1)
The Maze of Bones
39 Clues (1)
The Sea of Monsters
Percy Jackson and the Olympians (2)
The Titan's Curse
Percy Jackson and the Olympians (3)