I can't tell whether this is my favorite of the existing Percy Jackson stories. After a while, it has become just a story that I must read because it's in the series and there is no way that I can stop now! But it is definitely highly entertaining and I especially appreciate the fact that Riordan manages to make the young characters grow up convincingly as modern teens. I have a fascination with mazes and labyrinths so anything with this setting tends to make me happy, although I did not quite "feel" the labyrinth setting in this one since the entries and exits and twists and turns are all so disconnected. It did not quite have a "maze" feeling, unlike that in The Silver Chair or in The Tomb of Atuan. This is just Riordan's convenient way to "teleport" his characters to different parts of the world. Things are definitely magically convenient, but that is part of the charm of this series. One just knows that things will work out for the heroes. I wonder if Riordan will "pull a Rowling" in book five and have one of the main/major supporting characters die?

Oh, and I just realized that Thalia is not in the book and was only mentioned once or twice in passing.. what's going on THERE?

Nico is a good character and the plot surrounding him has not been as predictable. I liked that.

The story arc concerning Kronos' reincarnation is getting taut and tension is high and I hope there will be a huge pay off in either the next volume or the volume after that. But, I'm hoping that he does not drag the series on too long. Make it work, Riordan!