Percy Jackson and the Olympians Series Novels

The Last Olympian (Percy Jackson and the Olympians 5) by Rick Riordan
The Battle of the Labyrinth (Percy Jackson and the Olympians 4) by Rick Riordan
The Titan's Curse (Percy Jackson and the Olympians 3) by Rick Riordan
The Sea of Monsters (Percy Jackson and the Olympians 2) by Rick Riordan
The Lightning Thief (Percy Jackson and the Olympians 0) by Rick Riordan