D. Brent Chapman is a consultant in the San Francisco Bay Area, specializing in Internet firewalls. He has designed and built Internet firewall systems for a wide range of clients, using a variety of techniques and technologies. He is also the manager of the Firewalls Internet mailing list. Before founding Great Circle Associates, he was operations manager for a financial services company, a world-renowned corporate research lab, a software engineering company, and a hardware engineering company. He holds a Bachelor of Science degree in electrical engineering and computer science from the University of California, Berkeley. In his spare time, Brent is a volunteer search and rescue pilot, disaster relief pilot, and mission coordinator for the California Wing of the Civil Air Patrol (the civilian auxiliary of the United States Air Force).