The Song of the Quarkbeast by Jasper Fforde
The Last Dragonslayer. Having fulfilled the prophecy that she was unwillingly a part of in that book, Jennifer Strange, the teenage acting manager of Kazam, an employment agency for sorcerers, now finds herself once again at the center of events that could change the Ununited Kingdom forever.
Ever since the events of Dragonslayer, the level of magic that exists in the world has been on the rise. The sorcerers who work for Kazam can tell that the source of their powers is increasing, but they're not the only ones to have taken notice. King Snodd IV has realized what's happening as well, and he knows that if he can control magic, he can control everything. Only Jennifer Strange stands between Snodd and his plans.
The Song of the Quarkbeast and the Dragonslayer series as a whole are great, and both young adults and their parents will enjoy reading them. I think too often when writers, who normally write for an adult readership, make the transition to writing for a younger audience, they tend to inadvertently insult younger readers by "dumbing it down." Fforde doesn't do that. These books are just as intelligent as his "Thursday Next" and his "Nursery Crimes" books.
★ ★ ★ ☆ ☆