Every body talks of apparitions of angels and demons, and of souls separated from the body. The reality of these apparitions is considered as certain by many persons, while others deride them and treat them as altogether visionary.

I have determined to examine this matter, just to see what certitude there can be on this point; and I shall divide this Dissertation into four parts. In the first, I shall speak of good angels; in the second, of the appearance of bad angels; in the third, of the apparitions of souls of the dead; and in the fourth, of the appearance of living men to others living, absent, distant, and this unknown to those who appear. I shall occasionally add something on magic, wizards, and witches; on the Sabbath, oracles, and obsession and possession by demons.