I was expecting a hefty sci-fi novel for adults when I put this on hold at the library, but what arrived instead was a YA steampunk fairy tale. It was very enjoyable, and surprisingly clever! Set in a loosely defined dystopian future, the action begins in London, which is now a Traction city. The Traction cities of Europe roll over hills, plains, and the dusty beds of ancient long-dried oceans on massive wheels, chasing down smaller towns and devouring them. This is Municipal Darwinism at work, and Tom, a Third Class Apprentice in London's museum, has been taught that it is right and noble that the strong should grown stronger by ingesting the weak. Only when he falls from London and has to survive in a shattered landscape of deserts, marshes, pirates, slavers, rogue towns and Anti-Traction League spies does he begin to realize that what he grew up believing in might actually be monstrous.