Pendragon by D.J. MacHale

Bobby Pendragon never thought he would save the world. In fact, he never thought past winning the county semifinals in basketball or kissing Courtney Chetwynde. So when his Uncle Press drags him into another world, he's understandably upset, shocked, and outraged. But there are bigger issues than basketball or even Courtney. There is a great evil at work on Denduron, the alternate dimension Bobby finds himself in, and he is expected to stop it.

The Merchant of Death is the beginning of a ten book series by D.J. MacHale, with one book per world (known as a territory). Throughout the series, Bobby realizes his destiny as a Traveler...saving the universe. Of course. It sounds corny, but MacHale unfolds the intricacies of Halla in a way that leaves you one step behind, and looking for more. The separate conflicts of the territories are tied together by the scheming of Saint Dane, certified Bad Guy, along with the other Travelers that Bobby meets. Most enjoyable are the distinct cultures with their own people, technology, and problems.

Written in journal format, Pendragon is a gripping read. Bobby's snarky comments can go overboard sometimes, but usually make me chuckle aloud. It's definitely worth the read, and even more so for fans of Harry who need a little magic.