Book excerpt: With a target audience of computer security and other information technology professionals, Branigan (president, CyanLine LLC) focuses on the people more than the technology in his discussion of cybercrime and its investigation. He describes cases he's been involved with, some as a law enforcement officer, in order to give professionals an idea of how criminals exploit computer weaknesses and what can be done to catch them. After describing such episodes as an attack on a telephone network, an attack on an ISP, and a case of identity theft, he proceeds to a more general discussion of cybercrime, exploring such questions as why hackers hack and the proper conduct of criminal investigation.