TO ASSIST PROSECUTORS AND DEFENSE ATTORNEYS IN OBTAINING A CONCISE UNDERSTANDING OF THE SCOPE OF EXPERT INVESTIGATIONS AND THE NATURE OF THE RESULTS WHICH MAY BE EXPECTED FROM LABORATORY INQUIRIES, THE TEXT REVIEWS THE SCIENTIFIC TECHNIQUES WHICH ARE AVAILABLE TO TRIAL PRACTITIONERS. THE SPECIFIC LAW FOR EACH TECHNIQUE IS SET FORTH AS IT APPLIES TO THE LEGAL STATUS AND ADMISSIBILITY OF THE TEST RESULTS AS EVIDENCE. CONSIDERATION IS ALSO GIVEN TO THE QUALIFICATION OF EXPERT WITNESSES, AND TO CHALLENGING NONEXPERTS THROUGH CROSS-EXAMINATION. THE BASIC ELEMENTS IN THE SELECTION AND PREPARATION OF EXPERT TESTIMONY ARE DISCUSSED, IN CONJUNCTION WITH THE RIGHTS AND RESPONSIBILITIES WHICH AN ATTORNEY INCURS DURING THE PROCESS OF DISCOVERY. THE LEGAL ASPECTS OF A SPECTRUM OF SCIENTIFIC METHODOLOGY ARE PRESENTED INCLUDING ALCOHOLIC INTOXICATION TESTING, THE PRINCIPLES OF FIREARMS IDENTIFICATION, AND COMPARATIVE MICROGRAPHY. THE FIELD OF FORENSIC MEDICINE IS OUTLINED INCLUDING THE USE OF FORENSIC PSYCHIATRY, PSYCHOLOGY, NEUROLOGY, AND PATHOLOGY. A GENERAL PERSPECTIVE OF THE USE OF TOXICOLOGY, CHEMISTRY, AND SEROLOGY IS PRESENTED, WITH EMPHASIS ON THE EVIDENTIAL STATUS OF TEST RESULTS OBTAINED IN INVESTIGATIONS. THE CLASSIFICATION AND EVIDENTIARY USE OF FINGERPRINTS IS DISCUSSED, AS ARE THE MICROANALYTIC IDENTIFICATION AND COMPARISON OF SMALL OBJECTS AND PARTICLES. THE TECHNIQUES OF NEUTRON ACTIVATION ANALYSIS ARE TREATED AS THEY APPLY TO THE EXAMINATION OF QUESTIONED DOCUMENTS. ADDITIONAL DISCUSSION CONCERNS THE USE OF PHOTOGRAPHY, SPECTROGRAPHIC VOICE IDENTIFICATION, THE POLYGRAPH AND VOICE STRESS ANALYSIS, AND THEIR LIMITED AVAILABILITY AS EVIDENCE. CASE LAW CITATIONS, AN INDEX, DIAGRAMS, PHOTOGRAPHS, GLOSSARY, AND DETAILED TABLE OF CONTENTS ARE PROVIDED. (TWK)