Well-researched work on legitimate, proven, and tormenting paranormal content.
(Currently retitled as "Lure of the Occult"; despite the same content.)
If F. Martin's Hostage to the Devil was an eye-opener... this is scholarly, concise; with stories, concisely, yet brilliantly written. This is far more than typical "demonology", in that it covers astrology, magick texts, demonic spells, and MANY more concepts.
If even "demonology" is of interest to you, open your mind to a brilliant work by a Biblical scholar who has researched an immense amount of true material.