Halloween trick-or-treating probably originated with a ninth-century European custom called souling. On All Souls Day (November 2), early Christians would walk from village to village begging for soul cakes, square pieces of bread with currants. In exchange for the cakes, the beggars would promise to say prayers on behalf of the donor’s dead relatives. Thus the Halloween association with ghosts and souls in limbo. This week’s collection of Halloween treats are for those who like to read and write ghost stories.