The Lightning Thief
Author: Rick Riordan
I love this book. Some people think that its more of a children's book, and i did read it when I was younger, but I would absolutely read it again and you should too:) I have read every book in the series and I think this one is the best, with action, a wee bit of romance, and lots of adventure.
After learning that he is the son of a mortal woman and Poseidon, god of the sea, twelve-year-old Percy is sent to a summer camp for demigods like himself, and joins his new friends on a quest to prevent a war between the gods.
Overview from Barnes &Noble, Inc.
Picture from http://thatwasnotinthebook.com
Picture from http://riordan.wikia.com