Jean de Nynauld was a French physician who wrote an important work on lycanthropy in 1615 titled De la lycanthropie, transformation et extase des sorciers (On lycanthropy, transformation and ecstasy of witches).[1] de Nynauld saw lycanthropy as a form of mental illness rather than a form of magic.[2]
A critical edition of the work, edited by Nicole Jacques-Lefevre and Maxime Preaud, was published by Frenesie in Paris, 1990.