This report reviews past NRC studies that have examined various dimensions of computer and network security and vulnerability and brings the results forward into the context of the current environment of security and vulnerability. The review includes work done since 1991, such as Computers at Risk (1991), Cryptography's Role in Securing the Information Society (1996), For the Record: Protecting Electronic Health Information (1997), Trust in Cyberspace (1999), Continued Review of the Tax Systems Modernization of the Internal Revenue Service (1996), Realizing the Potential of C4I (1999), and Embedded, Everywhere (2001).