Percy Jackson is one of the best series I have read, ever. It easily sits in my top 3 most favorite series. The other series by Rick Riordan are also great, but this is the original series, and it reigns supreme over them.
When reading, I couldn’t wait to see what was next, the suspense, action and plot made this extremely enjoyable. Rick Riordan managed to make every part of this series interesting and filled with adventure. Some of my most favorite parts in this series are the parts when gods come face to face with demigods, especially towards the end of the last book, which made me laugh about a million times. Because of this, I can comfortably rate this series 5 Stars.
One important thing I want to mention is that there are several more continuation and spinoff series, with characters from this series, with The Heroes of Olympus being a direct continuation series. There are also several collections of short stories: The Demigod Files and The Demigod Diaries. These are all the mythological series by Rick Riordan, in my recommended order to read. Percy Jackson, The Heroes of Olympus, The Trials of Apollo, Magnus Chase, The Kane Chronicles, Crossovers, The Demigod Files and The Demigod Diaries.
Because of being super fun and engaging, while being relatively easy to understand, I can easily recommend this series to anyone ages 8+. Older people (Teenagers, Adults, Seniors) will also really like this series. This series is also a decent introduction to Greek mythology, albeit in an interesting, captivating way.