The Codex Alera is set in a typical medieval fantasy setting, but there also is a strong Roman Empire feel to the world. There is only one nation of humans on this world, and they are often beseiged by enemies from beyond the Empire. The story takes place out in the frontier. All the people of this world can control Elementals. These Elementals can control one either Air, Water, Fire, or Earth to a varying degree. A person's place in this world is often dependent on how powerful their Elemental happens to be and how many Elementals they control. The main character is a young boy named Tavi and he controls none; thus he's a bit of a freak.
He learns of a threat to the Empire and is forced to do his best to save it. Because he doesn't have any magic, he has to rely on courage, luck, friendship, intellect, and skill. The writing is good (not splendid but good enough), but what I liked is that the story just rockets along. It was just a fun read. It may not change your life, but it will definitely entertain you for a few hours.