The Wall and the Wing -- Laura Ruby

With her first six words -- “In a vast and sparkling city…” -- Laura Ruby had me.

In this vast and sparkling city, most people can fly.  Granted, not many of them can fly very high or for very long, but even those who only hover inches above the pavement for brief periods of time are better off than the leadfeet -- those who can't fly at all. 

And in this vast and sparkling city, there is a girl called Gurl.  An orphan, she lives at the Hope House for the Homeless and Hopeless.  She can't fly.  At all.

But she's just discovered that she can do something even better.  She can make herself invisible.

She hasn't even had time to explore her new talent before she learns that to some... unscrupulous... folk, a person who can become invisible at will is a hot commodity.

With the help of a brilliant, shower-taking, pasta-eating cat and a wall-punching, lock-picking boy called Bug, Gurl might just manage to avoid the baddies, explore her city and discover the truth about her past.

Gurl and Bug are instantly likeable, and the secondary characters are a hoot -- there's a gangster named Sweetcheeks Grabowski who has a scary zipper-faced sidekick, a professor with a dandelion growing out of his head, and an orphanage matron with a penchant for creepy toy monkeys who makes Miss Hannigan look positively classy.  The city, which, in many ways, bears a striking resemblance to NYC -- but a version of NYC populated with gangs of Rat-Men and Punks (males are all named Sid, females Nancy), albino alligators and actors in lion costumes who guard the entrance of the Public Library -- was my favorite character.

Laura Ruby has done something unusual in The Wall and the Wing.  (Some of you might want to sit down, here, this is a biggie.)  She tied up all of the loose ends.  This is not necessarily the beginning of a new series.  It works as a (GASP!) stand-alone.  She deserves a round of applause for that alone*. 

There were moments that reminded me of Pratchett, but it's an especially perfect pick for Eva Ibbotson fans.

*[Later:  According to the Booklist review, there is, apparently, a sequel in the works.  That doesn't change what I've said, though.  All.  Loose.  Ends.  Tied.  Up.  And besides, the city is too fun a place to not re-visit.]