The accomplished author of (among others) a serious YA novel, Pictures of Adam, and a compelling, tragic book for middle readers, Alan and Naomi, proves accomplished in another genre in this lighthearted fantasy. Since the death of their parents in a Sioux uprising (the cavalry mistook them for the enemy), Amy and Joshua have been virtual prisoners of wicked Aunt Vootch, who works them hard and punishes them often. They escape with Mortimer, an itinerant who is in many ways (including his eloquence) kindred to the Wizard of Oz; however, Mortimer's hat really is magic, and has a mind of its own, giving forth all sorts of unexpected things--including a line full of laundry, the smoke from a locomotive, and oddly assorted meals. With its help (and sometimes in spite of it), the three make it to New York, hoping to find the children's grandparents, which they do after another encounter with Aunt Vootch; and though the grandparents are unexpectedly poor (they live among recent immigrants on Broome Street), they are all able to construct a new, loving family. There are plenty of funny, lively incidents to keep this story hopping; the hat's shenanigans are especially imaginative. Clever wordplay, engaging characters, and the kind of sober undercurrent that makes true comedy more buoyant make this a fine addition to the short list of stories that truly entertain.