The author, Justine Larbalestier, is part of a renaissance in kids' fantasy and science fiction: genre fiction that takes the best elements of the literature's history and fuses it with contemporary settings and themes, a sort of Douglas Coupland meets JRR Tolkien that appeals to adults just as easily as kids. (her husband, Scott Westerfeld is also prominent in this)
"Magic or Madness" tells the story of Reason Cansino, a 15-year-old Australian girl whose crazy mother raised her nomadically in the bush, moving from settlement to settlement every few weeks. Reason is a math prodigy, and her mother has given her a thorough but eclectic education that is cut short by her mother's suicide attempt, which lands Reason in the clutches of her grandmother in Sydney. All Reason's life, her mother has warned her of her terrible, hateful grandmother, a woman who believes she is a witch, who sacrifices the family pet in the basement, who will take her and abuse her as she abused Reason's mother.
But Reason's grandmother doesn't appear to be the evil woman her mother warned her of, and Reason has to decide whom to trust.
"Magic or Madness" wonderfully mixes a genuinely creepy system of hereditary magic with Australian bush lore, sweet and canny details about New York's East Village, daily life in Australia, fashion and mathematics, sneaking lectures into dialog and description so subtly you never know they're there, only that you're getting the charge of soaking up new knowledge about how the world works.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.