The increase in information witnesses provide under hypnosis appears to be reflected primarily in decreased 'I don't know' responses to direct questions about the crime and is due to factors affecting recall and the witness's willingness to provide information. Forensic hypnosis processes improve recall by asking witnesses to retrace a string of events, including all sensory inputs, and helping them to avoid recall blocks that might result from undue attention to their memory gaps or level of uncertainty about those recollections. Moreover, many people are less guarded when talking to psychologists than police. However, several problems and limitations are associated with forensic hypnosis. Authorities indicate that hypnosis does not increase truthfulness. Subjects appear more susceptible to having their testimony biased by either leading questions or their prior conceptions and prejudices. Finally, the highly compelling manner in which even inaccurate testimony is presented by hypnotized witnesses may result in others being misled. Forensic hypnosis seems most appropriate when additional leads appear more important to solving a serious crime than the necessity for a witness to be completely accurate. Only experienced behavioral scientists should administer the technique, using a free narrative style of questioning, avoiding suggestions, and recording the initial statement on tape as a guide to more direct questions. Approximately 30 references are included.