This series was great! I didn't want it to end. But, I thoroughly enjoyed this book. It was non-stop action from the first page to the last. It was a little longer than the other books, but so much stuff was crammed into it. Nothing was left hanging, which I loved! All of the story lines came together and we finished getting the relevant back story for each of the the demi-gods. I enjoyed taking short breaks from the intense fighting to learn about each of the character's pasts. 
 This book also seemed funnier than the previous books in the series too! I would be reading about crazy battling for a while and then out of no where some cute or funny line would be thrown in to lighten the mood. I loved it! More than once I actually laughed out loud. The balance between intense adventure/battle scenes and lighter moments in the book was really enjoyable. 
 The twist with Rachel was really cool and I liked how she was worked into the storyline. I also loved how the sand dollar came into play. (Poseidon gave it to Percy in the 4th book, and told him to use it when the time was right. Ever since then, I was wondering when it would come up again) I really like it when a little detail can be woven into the story in such an interesting way. 
 The characters in this series are great! It is one thing to have a cool action/adventure story but when dealing with mythology there are so many fantastical creatures and gods that it can be hard to successfully incorporate them all. Rick Riordan did this in such a wonderful way. All his characters, and gods, and monsters were true to myth and seemed to leap off the page for me. They were so vivid, and I also loved that even though there were so many players in this series, none of them felt neglected to me. We learned so much about a ton of them, and I think this series really shone the spotlight and on a bunch of characters! That is not easy to do, so many times a series really only focuses on a few key players and the rest play background roles. I liked that this was not the case in Percy Jackson and the Olympians. 
 Percy is awesome! I love how mature he was throughout the series. (for the most part) And true to mythology, by the end of the book he had taught us all a lesson. (even the gods) I really enjoyed the development his character showed. 
 Another note on the characters- how are all of the myth animals so cute?? Seriously, I am in love with so many of them. Mrs. O'leary is awesome and so loyal! I got really scared a few times in the book that something might happen to her. Plus Bessie was adorable, swimming in her little tank on Olympus. And blackjack, the Pegasus. I want them all! 
 Overall, I LOVED this book, and the series! Anyone that likes mythology will love these books. They are so true to the excitement and adventure and fantasy that encompasses Greek mythology and they are a fun read that I truly enjoyed!