Book excerpt: The Public Broadcasting Service (PBS) and the WGBH Educational Foundation provide an online supplement to the "Frontline" television program entitled "Hackers." The program originally aired on February 13, 2001. The supplement and program focused on the vulnerabilities of the Internet, who computer hackers are, and laws that are supposed to protect Internet security. Interviews, tips for safeguarding computer files and personal data, and other materials are available online.