Ally Carter's Don't Judge a Girl by Her Cover is sheer fun. I'm always up for the Gallagher Girls and their adventures.
Here's the gist of the series: there's a super-secret school, Gallagher Academy, that trains girl spies (they're not spies now; just learning everything they'll need to know). Cammie Morgan is a pavement artist--skilled at following people, seeing what others don't. She'll need those skills to help protect one of her best friends, whose father is running for vice president.
The story ties in nicely to the previous books in the series, so you should really read those first. (On that note, who reads just one book in a series or skips around? And as I typed that sentence, I realized that I DO. Currently, I'm reading the second book in a loose series where I read book three first, followed by book one and now I'm on book two. Shame on me. But more on that later...)
Cammie is growing as a character and overall maturing, so that's nice to see. And yay for a certain character from book two making a few surprise appearances.
Anything, I like this series....it's fun, full of spies and is still somehow believable.