Experimental psychology contributes to hypnology and vice versa and it is pointed out that this mutual relationship should be looked at as a function of the significance of methodology in psychology and of the way in which such methodology has been developing. After reviewing the distinguishing features of the experimental, clinico-social and statistico-probabilistic approaches, the possibilities of using hypnosis as a technical tool for investigating general psychological problems or for throwing light on the diagnostic situation of a particular patient are investigated. The possibilities of using experimental psychological methodology for examining the hypnotic state in rigorous terms are then analysed and the need to systematize basic scientific research is stressed.
