Camp Half-Blood Chronicles is a collection of middle grade book series, standalone novels, short stories, graphic novels, and anthologies in Rick Riordan’s mythology-inspired fantasy franchise centered on the demigod children of the Greek and Roman pantheons. Since the Greek and Roman pantheons feature different aspects of the same gods, Riordan’s book series that feature Greek and Roman demigods both belong under the Camp Half-Blood Chronicles umbrella; the Greek and Roman demigods regularly interact with each other in-world.

Riordan also has two other book series—The Kane Chronicles and Magnus Chase and the Gods of Asgard—that take place within the same world and sometimes intersect with the Camp Half-Blood Chronicles. However, since these two series focus on Egyptian and Norse mythology, they do not belong to the Camp Half-Blood Chronicles franchise.

Camp Half-Blood Chronicles’ inaugural series, Percy Jackson and the Olympians, follows Poseidon’s son Percy, his satyr guardian Grover, and their friend Annabeth, daughter of Athena, as they save the world from the Titan Kronos. Nico is a minor side-character in this series: His sister Bianca dies in The Titan’s Curse. Will is introduced in the final book of the series, The Last Olympian.

Riordan was inspired to write these books because of his son’s attention-deficit/hyperactivity disorder (ADHD) and dyslexia.