Showing High Wizardry by Diane Duane

Don't take shrewd, eleven-year-old Dairine Callahan for just any bratty younger sibling. Impatient for adventure, knowledge, and recognition, maybe even a little jealous of her wizardly older sister, Dairine comes across Nita's copy of the Wizard's Manual and reads the Wizard's Oath aloud....

Disappointingly, nothing seems to happen. But when her family's new computer arrives, Dairine discovers that it's come with a whole lot more than the usual bundled software.

The computer contains a "beta" version of the new online edition of the Wizard's Manual. Wrapped up inside it is a whole world's worth of spells, secrets and magical knowledge...and it's all hers to play with.

Never the kind to do anything by halves, Dairine launches herself into a reckless, cross-universe, high-voltage magical conflict with the Lone Power. It falls to Nita and Kit to track Dairine down before she gets into trouble so deep that not even her precocious brains can save her.

But by the time they catch up with her, it's already too late. On a bleak and empty world, Dairine has already become the wizardly "godmother" to a brand new life-form. And the relentless Enemy of all new life is even now hot on her trail, intent on ending the threat Dairine poses...permanently.

"Pacing that doesn't let up from the very beginning...and a Heinleinesque affection for the characters. Duane writes about people you can really care about, with lots of quirks and endearing traits that feel real in a way most writers don't manage. ... Duane is a gifted storyteller." (Locus)

"The sheer effrontery of the plot -- coupled with the gritty charm of the characters and the sprightly dialogue of these credible siblings -- makes for enormous fun." (Kirkus)

A "Pick of the List" of American Bookseller Magazine