Justine Larbalestier

When Reason's mother goes insane, she is forced to live with her grandmother Esmerelda, who may be the source of her mother's insanity. Reason does her best to avoid contact with Esmerelda, but when she decides to run away her escape takes her from Australia all the way to New York. The book is full of action, a little violence, and is a good entry in the urban fantasy genre.