8.8/10 - Very entertaining and a fantastic start to an excellent series. The Percy/Annabeth/Grover dynamic is at it's best here. The scenes in the Underworld and at Camp Half-Blood are the best parts of the novel, easily. Harry Potter similarities, sure, but still good enough to hold the competition. Percy's narration is witty and the Greek Myths are updateded superbly. The ending twist is genius. Shame the film's didn't turn out so well.