The Un-Magician — Christopher Golden; Thomas E. Sniegoski

THE MOST DANGEROUS BOY IN THE WORLD?
TIMOTHY IS A FREAK, a weakling, an impossibility. He's the only person in existence without magical powers and has spent his entire life hidden on a remote island. When Timothy is finally taken back to the city of his birth, he is fascinated by the current of magic that fuels the world, and mesmerized by the buildings and orbs that hang weightlessly in the sky. But he is also marked for death.

Assassins are watching his every move, and the government wants him destroyed. Timothy can't imagine what threat he could possibly pose; after all, he wields no power in this world.

Or does he?

This book is also published as: Magic Zero: Book One of the Magic Zero Series