I've been reading Scott Lynch's Lies of Lock Lamora, a story about a crook so outrageously larcenous that at the age of seven or so the master of the local thieves' guild kicks him out (and nearly kills him) for stealing too much. Lynch must know something about that, because it appears he snuck into China Mieville's house, and stole his world-building and plot-building skills.
I may be exaggerating a bit. I am simultaneously reading Un Lun Dun to my four-year old (yeah, the vocabulary is a little heavy, but this is not your average kid). To be fair, Mieville has built a pretty interesting world with UnLondon (get it?), a place where all of the trash from London drifts to be attached into house walls or crawl along like pets. (A similarly composed No York is briefly mentioned in the book, but I can tell you from personal experience that our crap doesn't drift into other dimensions nearly fast enough.) UnLondon is fun, but it's not another Bas Lag.
What's worse about Un Lun Dun is that the protagonists, so far, haven't really done anything. I mean, they have been on a grand adventure, but Zanna the "Shwazzy" (or choisi, French for "chosen") hasn't really done anything to advance the plot herself, except for turning a boiler wheel that popped her into the world of UnLondon. And she didn't even do that by choice, she was more just kind of possessed. When the origin of the term Shwazzy was revealed in the book, the conjugation was interesting. The teacher explained the conjugation in the form "choisi - you have chosen." This would be the infinitive, if I understand it right. But so far, Zanna hasn't chosen anything. As far as what's happened to her so far, it makes more sense to say Zanna was chosen by someone else.
Locke Lamora is another matter. He's not a cutpurse or a cat burglar. He is an insanely ambitious con artist, a Frank Abagnale for the D20 set. Purchased from slavery as a child by the Thiefmaker, the owner of a gang of thieving children, Locke is sold to the high priest of a church for thieves after he scams his own master. This leads to the formation of the Gentlemen Bastards, a sophisticated con operation, which as I am reading is in the middle of performing a sophisticated pigeon drop on a naive but greedy member of the nobility.
Camorr, Locke's hometown, is clearly inspired by Venice, and is a lusciously byzantine place where everyone is constantly stealing from everyone else, where the less-successful thieves hang in nooses from the bridges while the nobles drift around on expensive pleasure boats burning their throats on hot ginger cocktails. Jonathan McCalmont has problems with the novel's over-labrynthine and slow-revealing plot structure, and I might change my mind. But right now, I can't wait to get back to the book.
I'm still really hoping Mieville's book picks up, or that I find out he's bounced back with a scary-violent grown-up book in keeping with what I've come to expect from him. China, the world of high fantasy needs you!