SECURITY SYSTEMS ARE GENERALLY CLASSIFIED INTO TWO CATEGORIES--PERIMETER AND INTERIOR AREA OR SPACE CONTROL. PERIMETER GUARD DEVICES ARE THE SIMPLEST, LEAST EXPENSIVE, AND EASIEST TO INSTALL. SUCH DEVICES INCLUDE STEP OR PRESSURE DOOR MATS, MAGNETIC SWITCHES, WIRED OR WOOD-DOWELLED SCREENS AND METALLIC WINDOW TAPE, CLOSED CIRCUIT TELEVISION, TRIP WIRES, AND LIGHTING. IN ADDITION TO SIMPLE LOCKS, INTERIOR PROTECTION DEVICES INCLUDE MANY TECHNOLOGICAL SYSTEMS--SEISMIC, INFRARED, ULTRASONIC, PHOTOELECTRIC, AND MICROWAVE--TO DETECT THE ENTRANCE OF INTRUDERS. IN WEIGHING THE ADVANTAGES AND DISADVANTAGES OF HIRING OUTSIDE GUARDS AS OPPOSED TO TRAINING AN INHOUSE FORCE, MANAGERS SHOULD FOCUS ON THE IMPORTANCE OF PROPER TRAINING PROGRAMS, EFFECTIVE EQUIPMENT (SUCH AS TWO-WAY RADIOS, PAGERS, AND GUARD DOGS), AND ESTABLISHED EMERGENCY PLANS. SECURITY AGAINST FIRE CAN BE PROVIDED THROUGH IONIZATION SMOKE-DETECTORS, SPRINKLER SYSTEMS, AND HAND-HELD FIRE EXTINGUISHERS. ALTHOUGH GUARDS ARE THE MOST EFFECTIVE DETERRENTS AGAINST VANDALISM, STEP OR PRESSURE MATS PROVIDE A USEFUL WARNING THAT VISITORS ARE DRAWING TOO CLOSE TO EXHIBITS. ALL OF THESE SECURITY ALARM SYSTEMS CAN BE TIED INTO CENTRAL STATION SYSTEMS, ON OR OFF THE PREMISES, WHICH RECEIVE THE EMERGENCY SIGNALS AND ACT ON THEM. SINCE NO SECURITY SYSTEM IS ABSOLUTELY FOOLPROOF, ART COLLECTORS AND INSTITUTIONS SHOULD KNOW WHAT TO DO IF THEY ARE VICTIMIZED, IN TERMS OF INSURANCE COVERAGE, RECOVERING STOLEN ART, AND CONTACTING DOMESTIC AND INTERNATIONAL AGENCIES. SPECIFIC SUGGESTIONS ARE PROVIDED TO PRIVATE COLLECTORS, GALLERIES, MUSEUMS, AND LIBRARIES TO DECREASE THE RISK OF ART THEFTS. A LIST OF SECURITY EQUIPMENT MANUFACTURERS AND AN INDEX ARE INCLUDED, ALONG WITH PHOTOGRAPHS AND DIAGRAMS. (KCP)