Neurypnology; or, The Rationale of Nervous Sleep

Neurypnology; or, The Rationale of Nervous Sleep is the founding treatise of scientific hypnotism, written by a surgeon who set out to debunk mesmerism and instead produced its first rigorous psychological theory. Its central claim is that the trance is a neuro-psychological state, induced by physiological means, with no need for any magnetic fluid or occult agency.

Braid demonstrates that the trance can be produced by having subjects fixate their eyes on a small bright object, fatiguing attention and the nervous system. He names the state "hypnotism" and later emphasizes the role of "monoideism"—the dominance of a single idea—and the subject's own focused expectation as its operative mechanism.

The book performed the pivotal act of demystification in this lineage, severing the phenomenon from Mesmer's cosmic fluid and grounding it in attention and belief. It made the subject respectable to medicine and cleared the ground for the French clinical schools and later suggestion therapy.