"Percy Jackson and the Olympians" is a five-book series. There are two companion books: "The Demigod Files," which contains short stories, puzzles, games and interviews, and the reference book, "The Ultimate Guide." A set of five more novels set in Percy Jackson's world feature others as the main characters.
The five novels of the "Percy Jackson and the Olympians" series are "The Lightning Thief," "The Sea of Monsters," "The Titan's Curse," "The Battle of the Labyrinth" and "The Last Olympian." The books follow the adventures of a modern-day American boy, Percy Jackson, who finds out that he is actually the son of a Greek god. In the first book, he meets other children of the Greek gods at Camp Half-Blood and must find the thief who stole Zeus' master thunderbolt.