In tracing the history of the Internet, it is useful to begin at its conceptual foundation. The Internet is an example of a type of network called a packet-switched network. These networks differ from telephone networks in a number of important ways. Technological differences aside, one significant difference between these networks is that packet-switched networks are designed to support a wide variety of applications, whereas the telephone network was designed to support one application (voice communications) optimally, though a few other applications are possible as well.

Intellectually, the origin of the Internet can be traced back to the early to mid-1960s, when Leonard Kleinrock, Joseph Licklider, Paul Baran, Lawrence Rogers, and others developed the ideas and theories underpinning these general purpose packet-switched networks. By 1967 some early experiments with using packet-switching technologies were taking place at the National Physical Laboratory in England. In 1969 the...