The benefits to medical practitioners of using the Internet are growing rapidly as the Internet becomes easier to use and ever more biomedical resources become available on line. The Internet is the largest computer network in the world; it is also a virtual community, larger than many nation states, with its own rules of behaviour or "netiquette." There are several types of Internet connection and various ways of acquiring a connection. Once connected, you can obtain, free of charge, programs that allow easy use of the Internet's resources and help on how to use these resources; you can access many of these resources through the hypertext references in the on line version of this series (go to http:@www.bmj.com/bmj/ to reach the electronic version). You can then explore the various methods for accessing, manipulating, or disseminating data on the Internet, such as electronic mail, telnet, file transfer protocol, and the world wide web. Results from a search of the world wide web for information on the rare condition of Recklinghausen's neurofibromatosis illustrate the breadth of medical information available on the Internet.