Hypnosis is described as a state of hypersuggestability accompanied by complete physical and mental relaxation. Hypnotized persons are aware only of the voice of the hypnotist, and their minds are focused entirely on carrying out suggestions and commands. For 90 percent of the subjects, a hypnotic trance is either of very light depth so that everything is remembered, or of medium depth so that only a hazy recollection of the trance activities remains. The other 10 percent experience deep trances. Hypnosis can be used to aid witnesses in recalling important events. It allows inordinately long periods of concentration without fatigue to develop. Recall is more accurate and vivid than in the waking state, and overlying emotional inhibitory factors are reduced to a minimum. Regression can be induced so that subjects can relive incidents as far back as childhood. In addition, hypno-analysis can be utilized to gain a critical analysis of witnesses' personalities: to learn whether they are stable, immature, highly imaginative, or prejudiced. Reluctant or frightened witnesses are provided with an excuse to divulge information without having accepted any strong sense of responsibility for doing so. Drawbacks of hypnosis include the need for lengthy sessions and properly trained personnel; the heightened imaginability which accompanies the trance; the requirement for a positive rapport between hypnotist and witness; and the reluctance of some witnesses to participate. Hypnosis is never used as a form of suspect interrogation, and it is not recommended for use in open court. Three references are provided.