Series
Els herois de l'Olimp
We don't know whether this one is finished.
Nobody has confirmed the status of this series yet. That's a gap in our data, not a verdict on the books.
3 books here
Publication order
This is publication order — nobody has confirmed a different reading order for this one yet.
2
The Son of Neptune
· Rick Riordan
3
The Mark of Athena
· Rick Riordan
4
The House of Hades
· Rick Riordan