Shadows by Robin McKinley because Robin McKinley, you guys, Robin McKinley. (She's one of the authors that I will always be eager to pick up and read, even if I do feel that her early work was some of her best.)
Maggie has stepfather problems -- namely, her new stepfather always seems to be accompanied by threatening, roiling shadows. In a world where technology has been developed to replace and subdue magic, the shadows seem unsettlingly like something that shouldn't be allowed to exist any more. Or maybe Maggie just isn't crazy about the idea of her mother getting remarried. As magic seems to strengthen its grip on Maggie's technology-focused world, Maggie learns that many things are not what they seem. Also dogs, boys, and a likeable Algebra textbook. (I know, that last one seems a little bit out there, but remember, it's fantasy.)
In some ways, this is very different from what McKinley has written before -- more teenage angst, and a setting that feels more like the future than the past -- but in other ways it is trademark McKinley. The dogs, for instance, and the way the magic works at the climax of the book, that I find hard to pin down but understandable in context. Also the rambling, which is one of McKinley's charms but may be irritating to some readers who don't want to go wandering off into backstory in the middle of a paragraph of dialogue. This isn't going to be up with Beauty and The Hero and the Crown as a new favorite McKinley, but it's sitting comfortably in the midrange.
(Reviewed from a copy borrowed through my library system.)