Percy Jackson and the Olympians by Rick Riordan.
The first five books are amazing. It will always be one of my all-time favorite series sold to young adults and is number two only to Harry Potter. You get a kid with what at first seems to be learning disorders such as ADHD and dyslexia but it turns out his mind is hardwired to read ancient Greek and survive odd combat situations. Percy also has a classic bit of sass when it comes to dealing with others, I found it very relatable. He does tend to run head first into his problems instead of thinking things through. He is helped by a fellow demigod Annabeth whom keeps Percy on track with his missions when he gets distracted by making a funny instead of stabbing the monsters. He is also helped by Grover, a satyr posing as a student sent to watch over Percy when he was in the normal world. Grover is pretty much Percy’s Ron... best friend. The first five books stick with Percy as the narrator.
Lightning Thief: the young boy Percy finds out he is related to the Greek gods and must help find Zeus’s missing master lightning bolt or Zeus will go to war with the his other siblings,
Sea of Monsters: Grover has gone missing while searching for a missing artifact. Percy again breaks the rules again and he and Annabeth go looking for him with a new Ally, Percy’s half brother.
Titans Curse: Percy must keep a mythical monster from being sacrificed by the minions of Kronos. We get to meet Bianca and Nico as well as Thalia.
Battle of the Labyrinth: Percy and crew find an entrance to the famed Labyrinth and must find a way to stop it from creating passages into their camp.
The Last Olympian: war has begun, the gods are off fighting Typhon, an ancient threat to their power. While they are away the minions of Kronos march on mount Olympus. If Percy and his friends don’t stop Kronos everything they know and love will be destroyed.
You can find out more on the series and the Author at http://www.rickriordan.com/