The Percy Jackson series was a little hit-and-miss for me. The first book was nearly pitch perfect. It was a fast-paced adventure that managed to be inventive and funny and have interesting characters. With each successive book the story moves further and further into the world of the gods. While this seems like a very logical move storywise, it is why I didn't enjoy the next four books as much as I expect I would.Part of the charm of the first book was the interaction between the world of the gods and the "real world" or world of mortals. That Percy had one foot firmly in each world made for funny situations. This lessens after the first book.
The Last Olympian pits Percy and the forces of good, which include most of the gods and many of the demigods against the Chronos and his forces, which include many of the lesser gods and also a large number of demigods. The final showdown takes place on the streets of New York City.
The Percy Jackson series started off with a bang. The Lightning Thief was excellent, but the rest of the books were not nearly as good. All in all, the series was just okay. It fell way short of His Dark Materials and Harry Potter.
I saw the teaser for The Lightning Thief before the latest Harry Potter movie. It looked cool. I expect that the movies will do well.
My review of The Lightning Thief (Book One)
My review of The Sea of Monsters (Book Two)
My review of The Titan's Curse (Book Three)
My review of The Battle of the Labyrinth (Book Four)
I liked the first book of this series a lot, and 
Twelve year old Percy Jackson has some problems. He is dyslexic and has ADHD to the max. As a result, he gets kicked out of every school in which his mother enrolls him. His stepfather is a jerk, and he doesn't know his real dad. As the book opens, Percy is on a field trip to the Met with his fellow classmates. Just a typical, boring field trip until one of the teachers turns into a Fury and tries to rip him in half. Percy realizes that dyslexia and ADHD are the least of his problems, when he discovers that he is a demigod -- half man, half god -- and that he is caught in the middle of a war that is threatening to tear the world apart, quite literally.