Anthology of true accounts and short fiction by Peter Haining, Montague Summers ('The Satanic Mass'), E.F. Benson ('The Sanctuary'), H.P. Lovecraft ('Ancient Sorceries', 'The Festival'), August Derleth ('The Watcher from the Sky'), Dennis Wheatley ('The Black Magician'), Aleister Crowley ('The Initiation'), Margaret Irwin, Cleve Cartmill, and Robert Bloch ('Spawn of the Dark One'); plus the newspaper stories 'Black Magic Battle in the Church' and 'Black Mass in a Park Starts Police Hunt'. Introduction by August Derleth.