Question: Who wrote the Percy Jackson books?
Context: Perseus "Percy" Jackson is a fictional character, the title character and narrator of Rick Riordan's "Percy Jackson & the Olympians" series.  He is also one of seven main protagonists of the sequel series "The Heroes of Olympus", appearing in every book except "The Lost Hero," and appears in the ongoing "Trials of Apollo" series, making him one of the few characters to appear in all three series of the Camp Half-Blood chronicles.  He has also been a narrator and protagonist in Riordan's Greco-Roman/Egyptian crossover stories, part of the "Demigods and Magicians" collection.  The character serves as the narrator in "Percy Jackson's Greek Gods" and "Percy Jackson's Greek Heroes", also by Rick Riordan. Camp Half-Blood Chronicles is a media franchise created by author Rick Riordan, encompassing three five-part novel series, three short-story collections, two myth anthology books, a stand-alone short story, an essay collection, a guide, four graphic novels, two films, a video game, a musical, and other media.  Set in the modern world, it focuses on groups of demi-god teenagers, and features many characters from Greek and Roman mythology.  The first series, "Percy Jackson & the Olympians", follows the adventures of a teen named Percy Jackson at a summer camp for Greek demigods.  The second series, "The Heroes of Olympus", introduces several more lead characters and a second camp for Roman demigods.  The third series, "The Trials of Apollo", follows the now-mortal god Apollo, with appearances by many characters from the first and second series. The Demigod Files is a collection of stories by Rick Riordan published on February 10, 2009.  It is a companion book to series "Percy Jackson & the Olympians".  It contains three short stories, titled "Percy Jackson and the Stolen Chariot", "Percy Jackson and the Bronze Dragon", and "Percy Jackson and the Sword of Hades", as well as a preview of "The Last Olympian".  It is set between the fourth and fifth novels, "The Battle of the Labyrinth" and "The Last Olympian". Percy Jackson's Greek Gods is a collection of short stories about Greek mythology as narrated by Percy Jackson.  It was written by Rick Riordan and was released on August 19, 2014.  It features Percy Jackson giving his own take on the Greek myths in a humorous way. The Lightning Thief is a 2005 fantasy-adventure novel based on Greek mythology, the first young adult novel written by American author Rick Riordan.  It is the first novel in the "Percy Jackson & the Olympians" series, which charts the adventures of modern-day twelve-year-old Percy Jackson as he discovers he is a demigod, the son of a mortal woman and the Greek god Poseidon.  Percy and his friends Annabeth Chase and Grover Underwood go on a quest to prevent a war between the gods Zeus, Poseidon, and Hades. Percy Jackson & the Olympians, often shortened to Percy Jackson, is a pentalogy of adventure and mythological fiction books written by American author Rick Riordan, and the first book series in the Camp Half-Blood Chronicles.  Five supplementary books, along with three graphic novels, have also been released.  More than 45 million copies of the books have been sold in more than 35 countries. Richard Russell Riordan Jr. ( ; born June 5, 1964), better known as Rick Riordan, is an American author.  He is known for writing the "Percy Jackson & the Olympians" series, about a twelve-year-old boy who discovers he is a son of Poseidon.  His books have been translated into 42 languages and sold more than 30 million copies in the US.  Twentieth Century Fox has adapted the first two books of his Percy Jackson series as part of a series of films.  His books have spawned related media, such as graphic novels and short story collections. The Heroes of Olympus is a pentalogy of adventure, mythological fiction and fantasy novels by American author Rick Riordan that collectively form a sequel series to the "Percy Jackson & the Olympians" series.  This series details a conflict between Greek and Roman demigods and Gaea, the earth goddess.  Riordan introduces Roman mythology into his sequel series as well as several new characters.  The first book of the series, "The Lost Hero", was published on October 12, 2010.  The final entry in the series, "The Blood of Olympus", was published on October 7, 2014. The Last Olympian is a fantasy-adventure novel based on Greek mythology by Rick Riordan, published on May 5, 2009.  It is the fifth and final novel of the "Percy Jackson & the Olympians" series and serves as the direct sequel to "The Battle of the Labyrinth".  "The Last Olympian" revolves around the demigod Percy Jackson as he leads his friends in a last stand to protect Mount Olympus.  The title refers to Hestia, the goddess of the hearth, who refers to herself as such in a conversation with Percy on Mount Olympus. Percy Jackson: Sea of Monsters (also known as Percy Jackson & the Olympians: The Sea of Monsters) is a 2013 American fantasy adventure film directed by Thor Freudenthal.  It is the second installment in the "Percy Jackson" film series and is loosely based on the novel "The Sea of Monsters" by Rick Riordan.  It is a stand-alone sequel to the 2010 film "".
Answer: American author Rick Riordan