Amand-Marie-Jacques de Chastenet Marquis of Puysgur

Amand-Marie-Jacques de Chastenet, Marquis de Puységur (1751–1825) was a French aristocrat and magnetizer from a prominent noble family. He is recognized as one of the early contributors to hypnotism, a branch of animal magnetism or Mesmerism. Puységur learned about Mesmerism from his brother Antoine-Hyacinthe and gained prominence after treating Victor Race, a peasant who exhibited an unusual sleeping trance state that Puységur termed "artificial somnambulism." This term later became associated with hypnosis, which was named by James Braid in 1842.

Puységur's approach emphasized belief and willpower, encapsulating his philosophy in the words: "Believe and want." His institute, Société Harmonique des Amis Réunis, grew significantly until the French Revolution, after which it dissolved and Puységur spent two years in prison. Despite being seen as a disciple of Mesmer, Puységur's methods were distinct and influential. His contributions were overlooked for many years but were later rediscovered by Charles Richet in 1884, who acknowledged Puységur's foundational work.

Puységur's role was highlighted by historians such as Henri Ellenberger, who regarded him as a "great forgotten contributor" to psychological sciences. Peter Sloterdijk also emphasized his importance in challenging the notion that Enlightenment intellectuals ignored the subconscious mind.