FOLLOWING A REVIEW OF THE DISTINCTION BETWEEN THE UTILITY OF PHYSICAL VERSUS VERBAL EVIDENCE, INTERVIEWING SELECTED TYPES OF WITNESSES IS DISCUSSED, WITH ATTENTION TO CHILDREN, ADOLESCENT WITNESSES, MIDDLE-AGED PEOPLE, AND OLDER INDIVIDUALS. THE COMMUNICATION PROCESS IS ANALYZED IN TERMS OF ENCODING (SELECTING WORDS AND IDEAS FORMING A LINE INQUIRY), DECODING AND INTERPRETING (DETERMINING THE INTENT AND MEANING OF A MESSAGE), REPLY (REVERSING THE ENCODING, DECODING, AND INTERPRETING PROCESS), AND TONE AND GESTURE (THE PARALANGUAGE AND KINESIC MESSAGES ACCOMPANYING THE ACTUAL VERBAL COMMUNICATION). FACTORS UNDERLYING SUCCESSFUL INTERVIEWING ARE IDENTIFIED, INCLUDING THE EFFECT OF THE INTERVIEWER'S APPROACH, PROBLEMS ASSOCIATED WITH NOTE-TAKING, AND THE LOCATION AND STRUCTURE OF THE QUESTIONING. HELPFUL HINTS FOR INTERVIEWERS ARE PROVIDED. THE PROCESS OF INTERROGATING A SUSPECT OR SOMEONE ATTEMPTING TO WITHHOLD INFORMATION IS DETAILED, WITH EMPHASIS ON CONFESSIONS, PRIVACY, PREPARATION FOR AND CONDUCT OF QUESTIONING, TYPES OF SUBJECTS, PHYSIOLOGICAL CHANGES (I.E., SWEATING, NERVOUSNESS, AND OTHER OBVIOUS CONDITIONS INDICATING POSSIBLE DECEIT), TECHNIQUES FOR EASING UNCOOPERATIVENESS CAUSED BY AN OVERWHELMING FEAR OF GUILT, AND THE GOOD GUY/BAD GUY TRICK. SUGGESTED READINGS ARE PROVIDED. (KBL)