how many percy jackson books are there

There are 18 books in the Percy Jackson universe as of 2025. This includes the original Percy Jackson and the Olympians series, which consists of 7 books, plus two sequel series—The Heroes of Olympus (5 books) and The Trials of Apollo (5 books). Additionally, there are stand-alone books like "The Sun and the Star" and some recent additions that bring the total to around 18 books within the overall Camp Half-Blood universe created by Rick Riordan.