THE VOICEPRINT TECHNIQUE IS BASED ON THE FACT THAT PRONUNCIATION OF WORDS OR PHRASES VARIES AMONG DIFFERENT SPEAKERS AND VARIATIONS AMONG DIFFERENT SPEAKERS ARE GREATER THAN VARIATIONS BY A SINGLE SPEAKER. THE SOUND SPECTROGRAPH TAKES THE TAPE RECORDED VOICE SOUNDS AND PRODUCES A GRAPHIC DISPLAY OF FREQUENCY VERSUS TIME. THESE ARE THEN COMPARED VISUALLY AS FINGERPRINTS OR HANDWRITING ARE COMPARED. THIS METHOD IS ACCEPTED AS A RELIABLE INVESTIGATIVE TECHNIQUE BY MANY STATE AND FEDERAL LAW ENFORCEMENT AGENCIES, WHILE A GROWING NUMBER OF COURTS ARE ACCEPTING VOICEPRINTS AS EVIDENCE. JUDICIAL DECISIONS RELATED TO THIS ARE BRIEFLY REVIEWED. THE EQUIPMENT USED AND THE PROCEDURES RECOMMENDED FOR COLLECTING RECORDINGS FOR SPECTROGRAPHIC ANALYSIS ARE COVERED IN DETAIL. THESE INCLUDE PROCEDURES FOR THE ROUTINE RECORDING OF CALLS TO THE POLICE AS WELL AS RECORDINGS COLLECTED ESPECIALLY FOR COMPARISON. PRECAUTIONS WHICH MUST BE TAKEN TO ENSURE THE PRINTS' ADMISSIBILITY AS EVIDENCE ARE SPELLED OUT. THE DISCUSSION ALSO COVERS UNWILLING SUSPECTS, LABORATORY REPORTS, AND PHYSICAL DELIVERY OF THE EVIDENCE TO THE COURT. APPENDED REFERENCES CONTAIN BOTH TECHNICAL DATA AND CASE CITATIONS. (GLR)