An Answer for Night-Hags is a book found on the bookshelf in Prospero's living room (The Face in the Frost, 2).
Inspiration[]
The night hag or old hag is a creature from the folklore of various peoples which is used to explain the phenomenon of sleep paralysis. It is a phenomenon during which a person feels a presence of a supernatural malevolent being (i.e. hag) which immobilizes the person as if sitting on his/her chest or the foot of his/her bed. The word "nightmare" was used to describe this phenomenon before that word acquired its modern, more general meaning. Various cultures have various names for this phenomenon and/or supernatural character[1].