Thus the "demonic" is properly understood less as a specific category of supernatural being than a collective reflection on unfortunate occurrences, on the ambivalence of deities, on tensions surrounding social and sexual roles, and on the cultural dangers that arise from liminal or incomprehensible people, places, and activities.

I can learn stuff from this book, but it's difficult and not fun to read. The other book is for a popular audience: The Eighth Tower, a.k.a. The Cosmic Question, by my favorite paranormal author, John Keel. Keel writes constantly about what the entities actually are, but rather than settling on a truth and defending it, he just spins out wild speculations with no attempt to make them consistent. It's great fun to read. A sample:

Over and over again the Bible tells us how men were instructed to create solid gold objects and leave them on mountain tops where the gods could get them. The gods were gold hungry. But why? ... If the ancient gods were real in some sense, they may have come from a space-time continuum so different from ours that their atomic structure was different. They could walk through walls because their atoms were able to pass through the atoms of stone. Gold was one of the few earthly substances dense enough for them to handle. If they sat in a wooden chair, they would sink through it. They needed gold furniture during their visits.