THE AUTHOR EXAMINES THE VULNERABILITIES OF EDP SYSTEMS AND DESCRIBES, STEP-BY-STEP, A TOTAL PROGRAM OF PROTECTION, FROM THE CONVENTIONAL ASPECTS OF PHYSICAL SECURITY TO SOPHISTICATED PROTECTION OF HARDWARE, SOFTWARE, AND COMMUNICATIONS. CHAPTERS DISCUSS WHERE TO LOCATE THE COMPUTER CENTER FOR UTMOST SAFETY, THE PRINCIPLES OF CONTROLLED CONCENTRIC PERIMETERS, THE SPECIAL RISKS OF REMOTE TERMINALS, NEWEST APPLICATIONS OF CRYPTOGRAPHY TO EDP, AND HOW TO MEASURE TELLTALE EMANATIONS. THE TEXT ALSO DEALS WITH EXPERIMENTS IN VOICE, SIGNATURE, AND FINGERPRINT IDENTIFICATION, PRINCIPLES OF ACCESS CONTROL, INTRUSION DETECTION AND SURVEILLANCE, THE 'SURVIVABILITY' FACTOR, AND OPERATIONAL AND SECURITY LOGS. A GLOSSARY OF TERMS, SAMPLE LOG FORMS, AND A BIBLIOGRAPHY ARE APPENDED. AN INDEX IS PROVIDED. (AUTHOR ABSTRACT MODIFIED).