Bob Ziegler graduated from the University of Wisconsin-Madison with an undergraduate degree in psychology, following near-completions in both German and philosophy. After taking educational and career trips in several directions, he decided to make his hobby his career and earned a master's degree in computer science, also from the University of Wisconsin-Madison. Out of school, Bob became one of a team of two UNIX operating system developers working for a company developing a mini-supercomputer. He developed a multiprocessor version of BSD 4.3 UNIX as a side project to the team's ongoing uniprocessor development efforts. Since then, he has worked as a UNIX operating system kernel developer for R&D companies in the Boston area. The advent of Linux and consumer access to 24/7 Internet connectivity gave Bob the keys to a dream he'd had since 1982 -- to have his own UNIX server and LAN at home. What began as a pragmatic effort to make his system secure on the Internet quickly grew into a passion for the home UNIX user. He offers free, web-based Linux firewall design services to the public, as well as a popular firewall and LAN FAQ to help people quickly get their Linux systems set up securely. Bob most recently functioned as a firewall architect at Nokia, collaborating wiht several groups in Massachusetts, California, and Finland. Carl B. Constantine has workin the computer industry for many years. He's been a programmer, consultant, technical writer, troubleshooter, and anything else he could get his paws into. Carl lives in beautiful Victoria, British Columbia, Canada, with his wife, Terry, and four children, Rebekah, 6, Emily, 4, Matthew, 2, and Joshua, 6 months. Carl is a programmer analyst/UNIX system administrator for the Department of Computer Science at the University of Victoria, in Victoria, British Columbia, Canada.