Kay Harker, hero of The Midnight Folk is again the hero --and, if you set up any precedents on that book, this is a natural follow through. If not -- the story stands alone, and the market is that of The Phoenix and the Carpet and other fantasy --adventure tales. The villains of the tale are an underworld gang with no scruples and magic powers. Fortunately the surprise box does its bit. Judith Masefield, daughter of the author, is the illustrator.