Bill Cheswick has worked on (and against) operating system security for over 30 years. While at Bell Laboratories as a member of the Technical Staff, he did early work on firewall design and implementation, including the first circuit-level gateway, for which he coined the term "proxy". Ches also worked on PC viruses, mailers, Internet munitions, and the Plan 9 operating system. He co-authored the first full book on firewalls, and has since toured the world giving media interviews and entertaining post-lunch security talks. Cliff Stoll, who is given to overstatement, has called Ches "one of the seven avatars of the Internet." In 1998, Ches started the Internet Mapping Project with Hal Burch. This work became the core technology of a Bell Labs spin-off, Lumeta Corporation, which explores the extent of corporate and government intranets and checks for host leaks that violate perimeter policies.