A princess of Landover / Terry Brooks.

Enhanced descriptions from Syndetics:

After fourteen years, New York Times bestselling fantasy master Terry Brooks has returned to the magic kingdom of Landover. The remarkable realm of dragons, demons, wizards, and wonders that wove an irresistible spell in five classic novels throws open its gates at long last for a brand-new adventure featuring a dazzling cast of characters and creatures.

Ben Holiday, Chicago lawyer and mere mortal turned monarch of enchanted Landover, has grappled with scheming barons, fire-breathing beasts, diabolical conjurers, and extremely wicked witches. None of whom have prepared him for the most daunting of challengers-a teenage daughter. Sent by Ben and his beloved sylph bride, Willow, to an exclusive girls' prep school, headstrong (and half-magical) Mistaya Holiday has found life in the natural world a less than perfect fit. And when her latest rebellious antics get her indefinitely suspended, she's determined to resume her real education-learning sorcery from court wizard Questor Thews-whether her parents like it or not.

But back home in Landover, Mistaya's frustrated father is just as determined that the precocious princess learn some responsibility, and he declares her grounded until she successfully refurbishes the long-forsaken royal library. Mortified by the prospect of salvaging a king's ransom in moldy books-and horrified by word that repulsive local nobleman Lord Laphroig seeks to marry her-Mistaya decides that the only way to run her own life is to run away from home.

So begins an eventful odyssey peppered with a formidable dragon, recalcitrant gnomes, an inscrutable magic cat, a handsome librarian, a sinister sorcerer, and more than a few narrow escapes as fate draws Landover's intrepid princess to the last place she expected to go, and into the thick of a mystery that will put her mettle to the test-and might bring the kingdom to its knees.