This book is broken down into 6 parts. The first describes the emergence of a worldwide network of computers, here called Worldnet, and the practices that people have engaged in as a result. The second part describes the problem of electronic breakins. The third part deals with the phenomenon of worms. The fourth part deals with viruses. The fifth part of the book gives a glimpse of the worlds in which hackers live. The final part deals with the social context in which people make ethical and moral interpretations and propose new laws. Prominent computer scientist Peter Denning defines and distinguishes among the various kinds of attacks--intrusions, worms, and viruses. His book addresses the vulnerabilities inherent in a networked world through the stories of two major incidents that attracted national attention: the Internet Worm and the Wiley Hacker.