THE FIVE MAJOR AREAS OF CONCERN -- PHYSICAL ASPECTS, MAGNETIC MEDIA CONTROL, TERMINAL SYSTEMS, DATA SET CONTROL, AND DISASTER RECOVERY -- ARE EXPLORED IN RELATION TO COMPUTER CONFIDENTIALITY, LARCENY, PRIVACY, CIVIL AND CRIMINAL LIABILITY, AND ASSETS PROTECTION. SELECTIVE PROTECTION AND COMPARTMENTATION ARE DISCUSSED IN DETAIL AS EFFECTIVE PROCEDURES ALTERNATIVES TO THE SEARCH FOR TOTAL PROTECTION. BASIC ELEMENTS WHICH CAN AND SHOULD BE USED BY ALL INSTALLATIONS, REGARDLESS OF SIZE, SCOPE, OR MISSION, ARE SET FORTH. THE TEXT IS DESIGNED FOR CORPORATE EXECUTIVES, DATA PROCESSING PROFESSIONALS, AND COLLEGE STUDENTS. APPENDIXES PRESENT CLASSROOM QUESTIONS, A SAMPLE FORMALIZED DATA PROCESSING SECURITY ASSESSMENT, AND A TYPICAL DATA PROCESSING INSURANCE POLICY. A BIBLIOGRAPHY AND AN INDEX ARE PROVIDED. (AUTHOR ABSTRACT MODIFIED).