I had to read this book after watching the film. The Lightning Thief is a great young adult novel. It has all the elements that resonate with the Middle School-aged student: a child who feels left out, a step-parent that acts horribly toward the main character, a loving mother, a place where the unique, out-of-place youth can identify with others, and a major quest that only the youth can accomplish.
In this way, Percy Jackson is a lot like Harry Potter. Instead of witchcraft and sorcery, we're talking about Greek mythology and the gods.
Riordan has hit it out of the park with this first book. I'm looking forward to continuing this series.
The book is much different than the movie. Because of time constraints, much of the story needed to be condensed; but here, in the novel, you will get the full brunt of the betrayal and the insidious plot behind the stealing of Zeus' bolt.
The book is much better than the movie because the big reveal sets up the rest of the series.
The movie is better than the book because there aren't too many villains and backstabs to follow and some of the extra story is left out to streamline a well crafted visual representation.