In celebration of finally (after five years) finishing this series (it's me not you), prepare for the reviews of the next books some time soon!
First, I need to admit that I like Greek mythology. Also, I was looking for something that would fill the hole the Harry Potter-series had left. Is this that series? It has similarities but Camp Halfblood is nowhere near Hogwarts.
Percy has tried, but isn't an easy child. He doesn't know why. This changes after events take him to Camp Halfblood and he learns that not only are the Greek Gods still alive, he's the son of one of them. This would be the start of a very nice series that tries to interweave the old myths and stories together with Greek mythology.
And that's what I liked most about the book. It's not always subtle, like Medusa owning an ornamental garden statue shop, but it does make some sense. The story is mostly a bit too the younger side of YA, but that didn't bother me.
One advice: don't watch the awful movie they made from this book!
The Lightning Thief is the first book in the Percy Jackson and the Olympians-series.
I read a Dutch translation of this book.