In reading order
The Lightning Thief
Rick Riordan
The Sea of Monsters
Rick Riordan
The Titan's Curse
Rick Riordan
The Battle of the Labyrinth
Rick Riordan
The Last Olympian
Rick Riordan
Percy Jackson: The Demigod Files
Rick Riordan
Percy Jackson and the Olympians: The Chalice of the Gods
Rick Riordan
Percy Jackson and the Olympians: The Chalice of the Gods
Rick Riordan
Wrath of the Triple Goddess
Rick Riordan
Percy Jackson and the Olympians: Wrath of the Triple Goddess
Rick Riordan
The Heroes of Olympus: The Demigod Diaries
Rick Riordan
Demigods and Magicians
Rick Riordan
From Percy Jackson: Camp Half-Blood Confidential
Rick Riordan