The Element Encyclopedia of Witchcraft: The Complete A-Z for the Entire Magical World - Judika Illes 2005
Trolls are skilled shape-shifters. Modern children’s stories suggest that trolls are generally hulking, stupid, and ugly. Folk wisdom agrees that trolls can be fierce and scary-looking but this is only half the story—the male half. Female trolls are fierce but beautiful.
Trolls live in communities paralleling those of humans, under hills and in barrows and caves filled with so much treasure that they glow in the dark. They love music and dancing and have been known to abduct musicians to play for them. They don’t like noise, especially the ringing of church bells, and thus try to live far from human habitation—although humans habitually encroach on their turf.
Trolls, like elves and sidhe, may refer to Pagan spirits, to human devotees of those forbidden spirits attempting to maintain their traditions apart from mainstream society, or to aboriginal people pushed to the margins by Indo-European invaders. In all cases, they are identified with magical arts, herbalism, and ironworking. In parts of Scandinavia, trollkvinna—“troll queen”—is synonymous with “witch.” (See DICTIONARY: Trollkvinna.)
Despite their negative reputations, many tales exist of benevolent, helpful trolls. On the other hand, they are also among those spirits frequently accused of stealing women, children, and valuables. Trolls are expert spell-casters, herbalists, and master ironworkers. They are nocturnal. Stories suggest that they turn to stone when exposed to sunlight.