The first internet
Computer networks, in any real sense, didn't exist until the ARPANET was built starting in 1969.
On October 4, 1957, the Soviet Union launched Sputnik, the world’s first manmade satellite into orbit. After Sputnik’s launch, many Americans began to think more seriously about science and technology. Schools added courses on subjects like chemistry, physics and calculus. Corporations invested in scientific research and development. The federal government formed the National Aeronautics and Space Administration (NASA) and the Department of Defense’s Advanced Research Projects Agency (ARPA), to develop space-age technologies such as rockets, weapons and computers.
The initial idea of the internet is credited as being Leonard Kleinrock's after he published his first paper entitled "Information Flow in Large Communication Nets" on May 31, 1961.
In 1962, a scientist from M.I.T. and ARPA named J.C.R. Licklider proposed a solution to the concern about what might happen in the event of a Soviet attack on the nation’s telephone system: a “galactic network” of computers that could talk to one another and that would enable government leaders to communicate even if the Soviets destroyed the telephone system.
In addition to the ideas from Licklider and Kleinrock, Robert Taylor helped create the idea of the government’s computer network, which later became ARPAnet.
In 1965, another M.I.T. scientist developed a way of sending information from one computer to another that he called “packet switching” so that each packet of data can take its own route from place to place. Without packet switching, the government’s computer network would have been just as vulnerable to enemy attacks as the phone system.
On July 3, 1969, UCLA puts out a press release introducing the Internet to the general public.
At 10:30 pm on 29 October 1969, ARPAnet delivered its first message: a “node-to-node” communication from one computer to another. (The first computer was located in a research lab at UCLA and the second was at Stanford Research Institute's; each one was the size of a small house.) The message—“LOGIN”—was short and simple, but it crashed the fledgling ARPA network anyway: The Stanford computer only received the note’s first two letters. About an hour later, having recovered from the crash, the computer at UCLA effected a full login.
As ARPAnet grew, in 1973 Vinton Cerf at Stanford started working on a better host-to-host protocol. In the following 5 years, he invented the twofold Transmission Control Protocol / Internet Protocol.
TCP/IP allows for the "handshake" that introduces distant and different computers to each other in a virtual space.
TCP/IP became the required protocol of ARPANET in 1983, also allowed ARPANET to expand into the Internet, facilitating features like remote login via Telnet and, later, the World Wide Web.
In 1989, the ARPANET officially became the Internet and moved from a government research project to an operational network; by then it had grown to more than 100,000 computers.
ARPANET itself was finally decommissioned in 1990.
The Internet took its current form since 1993.
References and useful resources: