A sweet, subversive fairytale about an eldest daughter named Sophie who's turned into an old woman by the Wicked Witch of the Waste. She goes to the ominous castle of the Wizard Howl to seek a cure for the curse, and ends up making a deal with Howl's captive fire-demon: if she manages to free him, the fire-demon will remove the curse.
I'm both very surprised and not really surprised at all that Howl's Moving Castle is Jones' most famous novel. Surprised, because in comparison with novels like Power of Three and A Tale of Time City it's fairly straightforward as a tale; unsurprised, because it is a nice book which does a good job of overturning typical fairytale stereotypes (the young, beautiful heroine, the evil stepmother, the uncomplicated happy-ever-after). I enjoyed it as a light afternoon read. It's a pretty, whimsical thing, full of originality and thought, but nothing particularly mind-blowing.
Calcifer is awesome, though.