Pioneers of an "Intergalactic Computer Network"
It was computer pioneer J.C.R. Licklider who first articulated a vision of something resembling an Internet system in 1963. As the head of the Information Processing Technology Office (IPTO) at the Advanced Research Projects Agency (ARPA) of the U.S. Ministry of Defense, Licklider addressed a memo to "Members and Affiliates of the Intergalactic Computer Network." In the note Licklider theorised that computers might help researchers share information. He even foresaw a day when communities of people with common interests could communicate with each other online -- by that time a novel thought.
At Lincoln Labs in Massachusetts computer expert Larry Roberts shared Licklider's view. Roberts saw the potential benefits of networking computers together; like Licklider he believed that networking would encourage "a 'community' use of computers." Roberts used a dedicated phone line to connect a computer at Lincoln Labs to a computer at the Systems Development Corporation in Santa Monica. Although this rudimentary link permitted his computer to log on to the other and run programs there, it was prohibitively expensive and not practical on a larger scale. But it was a start.

Arpanet, precursor of Internet
The first step for developing a world wide interconnection of computer networks was taken by the Government of the United States in 1969. Based on a purely military purpose the network should guarantee the availability and exchange of classified data in times of crisis by remaining in function even if large parts of it were to be destroyed. An agency of the United States Department of Defense, ARPA (Advanced Research Projects Agency) underwrote the development of the Internet and designed the precursor of the current network, known as Arpanet. In case of loss of any group of computer sites, the remaining sites should still be able to communicate along alternate routes.
No site would be critical to the operation of the network. Eventually, Arpanet was divided into Milnet, which connected military sites, and a new, public ARPANet that connected other sites, mainly universities.