A Treatise on the Incubus, or Night-Mare, Disturbed Sleep, Terrific Dreams and Nocturnal Visions

In the early nineteenth century, a doctor sat down to write about the creature that visited him in the night. He called it the night-mare: that weight on the chest, the throat pressed closed, the terror of waking unable to move. John Augustine Waller had suffered these episodes himself, and in this treatise he attempted what was then radical, to understand them through reason rather than superstition, through observation rather than prayer. This is not a medieval text conjuring demons, though demons once filled this space in the popular imagination. Waller approaches the incubus as a physician examines his patient, gathering accounts from his own experience and others', tracing patterns in diet, sleep position, and constitution. He seeks remedies in ancient practice and his own experiments, while navigating between the emerging language of medicine and older folk explanations that had not yet been fully displaced. The work endures because it captures a peculiar historical threshold: the moment before science could fully explain what happens in that threshold state between sleep and waking, when the supernatural had not yet been entirely excised from the bedroom. It is for readers curious about how we once understood the night terrors that still visit us, and for those interested in the strange, fumbling early history of sleep science.