This is one of Wellman's John the Balladeer/Silver John books. They're stand alone books set in rural America. Think the Ozarks, Appalachians, etc. John is a wanderer who travels with his guitar strung with silver strings, a store of stories and a general knowledge of American folklore. He lends a hand to help out with problems of mundane or supernatural origins.

This particular books deals with John trying ot over come a race of evil supernatural beings and their worshippers. It's interesting and fast paced. It's hard to find, and very enjoyable. ( )