William R. Cheswick (http://cheswick.com) is Chief Scientist at Lumeta Corporation, which explores and maps clients' network infrastructures and finds perimeter leaks. Formerly he was a senior researcher at Lucent Bell Labs, where he did pioneering work in the areas of firewall design and implementation, PC viruses, mailers, and Internet munitions.
Steven M. Bellovin (http://stevebellovin.com) is a Fellow at AT&T Labs Research, where he works on networks, security, and, especially, why the two don't get along. He is a member of the National Academy of Engineering and is one of the Security Area directors of the Internet Engineering Task Force. Long ago he was one of the creators of NetNews.