The Internet began in the late 1950s when programmers were looking for a solution to batch processing. So the concept of time-sharing was created allowing multiple users to share the processing power of the computer. During the same time the U.S. developed DARPA with the main goal of a network of inter-connected computers. This network (ARPANET) was intended to facilitate the exchange of research and prevent duplicates. These scientific networks along with the ARPANET became the foundation for the Internet we know today.
By the 1980s ARPANET had more than 200 networks. The 80s also brought about the personal computer. At the time Internet use was resricted to education and research. However there was a growing demand for better communication between corporations which lead to limited access for electronic mail.
Finally in 1991 the National Science Foundation Network allowed four large telecommunicaton companies to operate access points. They would sell access to Internet service providers who would then sell access to businesses and individuals.