The Book of Dead Days by Marcus Sedgwick

This creepy fantasy, seemingly set in Medieval times, tells the story of Valerian, a disagreeable magician, and his servant named "Boy." Valerian treats Boy badly (as you can guess by the fact that he never gave him a real name). He orders him around, punishes him for the slightest mistakes, keeps him up all night long running mysterious errands, and doesn't provide him with much in the way of food and clothing. After a sudden death at the theater where Valerian performs, a young girl named Willow, servant to another performer at the theater, turns to Boy for help. They both end up helping Valerian in his desperate search for a book which he says he must find before the end of the "Dead Days," the days between Christmas and New Year's Day, or else he will be dead. Did Valerian really make a pact with the Devil? Is his friend Kepler, the inventor, really helping him or is he sabotaging him? The book keeps you guessing until the very end. Review by Stacy Church