Simson Garfinkel is a computer consultant, science writer, contributing editor at WIRED Magazine, editor-at-large for Internet Underground, and senior editor at SunExpert magazine; he is also affiliated with many other magazines and newspapers. He is the author of PGP: Pretty Good Privacy (O'Reilly & Associates), NeXTStep Programming (Springer-Verlag), and The UNIX-Haters Handbook (IDG). Mr. Garfinkel writes frequently about science and technology, as well as about their social impact. Eugene H. Spafford is on the faculty of the Department of Computer Sciences at Purdue University. He is the founder and director of the Computer Operations, Audit, and Security Technology (COAST) Laboratory at Purdue and is also associated with the Software Engineering Research Center (SERC) there. Professor Spafford is an active researcher in the areas of software testing and debugging, applied security, and professional computing issues. He was a participant in the effort to bring the Internet worm under control; his published analyses of that incident are considered the definitive explanations. He is the coauthor of Practical UNIX Security (O'Reilly & Associates, second edition, 1995) and has also coauthored a widely praised book on computer viruses. He supervised the development of the first COPS and Tripwire security audit software packages, and he has been a frequently invited speaker at computer ethics and computer security events around the world. He is on numerous editorial and advisory boards, and is active in many professional societies, including ACM, Usenix, IEEE (as a Senior Member), and the IEEE Computer Society. He is involved with several working groups with IFIP Technical Committee 11 on Security and Protection in Information Processing Systems.