SINCE 1970, INVESTIGATORS IN THE LOS ANGELES POLICE DEPARTMENT, WITH THE AID OF DR. MARTIN REISER, DIRECTOR OF BEHAVIOR SCIENCE SERVICES IN THE DEPARTMENT, HAVE USED HYPNOSIS IN PARTICULAR CRIMINAL CASES, NOTABLY THOSE INVOLVING HOMICIDE, KIDNAPING, AND RAPE. DR. REISER REPORTED A 60 PERCENT INCREASE IN SUCCESS OVER TRADITIONAL INTERVIEWING TECHNIQUES. WHEN USED AS AN INVESTIGATIVE TOOL, HYPNOSIS ATTEMPTS TO ELICIT ESSENTIAL INFORMATION FROM COOPERATIVE SUBJECTS WHO ARE NOT SUSPECTS IN THE CASE. THE EFFECTIVENESS OF HYPNOSIS IN RECALL IS BASED IN ITS FACILITATING THE CONSCIOUS PORTION OF THE BRAIN TO DRAW FORTH MEMORIES FILED IN THE BRAIN'S UNCONSCIOUS. IT IS COMMON FOR WITNESSES OR VICTIMS INVOLVED IN EMOTIONAL EVENTS TO BLOCK FROM CONSCIOUSNESS EVENTS AND OBSERVATIONS IMPRINTED ON THE UNCONSCIOUS. TECHNIQUES OF HYPNOSIS INCLUDE; (1) REGRESSION, WHICH TAKES THE SUBJECT BACK IN TIME TO RELIVE THE EVENTS AT ISSUE EMOTIONALLY AS WELL AS FACTUALLY; (2) TELEVISION DOCUMENTARY OR MOVIE SCREEN, WHERE THE SUBJECT IS ASKED TO REPORT EVENTS AS THOUGH THEY WERE BEING VIEWED ON A TELEVISION OR MOVIE SCREEN; (3) FINGER RESPONSE, WHERE THE SUBJECTS IS TO GIVE 'YES' OR 'NO' ANSWERS TO QUESTIONS WITH FINGER TAPS; (4) AUTOMATIC WRITING, WHERE THE SUBJECT IS ASKED TO WRITE AUTOMATICALLY A RECORD OF WHAT IS RECALLED; AND (5) A TECHNIQUE WHICH ASKS THE SUBJECT TO RECALL SOMEONE'S APPEARANCE, WITH AN ARTIST PRESENT TO TRANSLATE THE DESCRIPTION INTO AN IMAGE. JUDICIAL DECISIONS REGARDING THE USE OF TESTIMONY OBTAINED THROUGH HYPNOSIS GENERALLY ALLOW ITS ADMISSIBILITY, BUT WITH ACCOMPANYING INSTRUCTIONS BY THE JUDGE THAT SUCH WITNESS TESTIMONY DERIVED FROM REGULAR RECALL. CASE STUDIES OF EFFECTIVE USES OF HYPNOSIS IN CRIMINAL INVESTIGATION ARE PROVIDED, AND THE INTERVIEW STRUCTURE USED BY THE NORTH TEXAS STATE UNIVERSITY INVESTIGATIVE HYPNOSIS PROGRAM IS DESCRIBED. (RCB)