The papers address methods for assuring computer system security by considering basic elements of protection (i.e., isolation, controlled access, and identification) and issues involved in certifying a system as secure (i.e., semantic, technological, and administrative). They review design approaches available to achieve these elements of protection and discuss problems involved in failure testing. One paper reviews security considerations for computer hardware and software and illustrates major weaknesses in contemporary operating systems. Security threats and security verification techniques are described. The papers suggest that better system design would be helpful in testing and verifying systems. Future efforts in this area should be spent on model development, production methodology, and automated test tools. Diagrams, tables, and chapter references are supplied. For individual papers, see NCJ 89656-60.