Alexis Didier (1826-1886) was a French clairvoyant whose extraordinarily accurate readings, carried out while he was in a hypnotic trance, attracted widespread notice during the mid-nineteenth century. Didier’s ability was tested with favourable results by the stage magician Jean-Eugene Robert-Houdin. Latest entry in the SPR's Psi Encyclopedia: https://psi-encyclopedia.spr.ac.uk/articles/alexis-didier