Rick Riordan's "Percy Jackson" series consists of five books, beginning with "Percy Jackson & The Olympians: The Lightning Thief" and ending with "Percy Jackson & The Olympians: The Last Olympian." The books are set in a universe that looks very much like our modern-day world but also includes the Greek gods as well as monsters from the Greek myths.
Riordan himself taught middle school social studies and English for several years, among other teaching experience. "I taught mythology almost every year that I was a teacher," the author writes on his website. "It was always my favorite thing, and the students always liked it, too!"
The author says he got the idea for the "Jackson" series when his son, Patrick, asked him to tell the Greek legends as bedtime stories. "When I ran out of myths, he was disappointed and asked me if I could make up something new with the same characters," Riordan said. The author created Percy Jackson and told Patrick the story of Percy's quest for the lightning bolt.