IT IS NOTED THAT AS THE NUMBER AND COMPLEXITIES OF MODERN MECHANICAL IMAGE RECORDING DIVICES INCREASES, THE DOCUMENT EXAMINER WILL INCREASINGLY BE REQUIRED TO RECORD AND COMPARE THE CHARACTERISTIC IMPERFECTIONS ASSOCIATED WITH THESE INSTRUMENTS. THIS IMPLIES THAT ALL DOCUMENT EXAMINERS SHOULD HAVE AT LEAST AN APPRECIATION OF THE VARIOUS CASTING TECHNIQUES CURRENTLY EMPLOYED FOR THE PRESERVATION AND RECORDING OF TOOL MARK IMPRESSIONS. SOME OF THE ADVANTAGES THAT CASTING PROVIDES OVER PHOTOGRAPHY FOR RECORDING TOOL IMPRESSIONS ARE LISTED. CASTING TECHNIQUES USED BY DOCUMENT EXAMINERS, THE PURPOSES FOR TOOL MARK IDENTIFICATION, AND THE TYPES OF TOOL MARK EXAMINATIONS ARE DISCUSSED. SILICON RUBBER PRODUCTS, THERMOPLASTICS, AND METALS ARE DESCRIBED AS THE MOST EFFECTIVE CASTING MATERIALS FOR RECORDING TOOL IMPRESSIONS. SILICON RUBBER BASE COMPOUNDS ARE RECOMMENDED FOR INITIAL USE BECAUSE OF THEIR RELATIVELY LOW COST, AVAILABILITY, EASE OF APPLICATION, ADAPTABILITY ON A VARIETY OF IMPRESSIONS, AND EXCELLENT FIDELITY OF REPRODUCTION. (RCB)