The underlying ideas of the Web can be traced as far back as 1980, when, at CERN in Switzerland, Sir Tim Berners-Lee built ENQUIRE (a reference to Enquire Within Upon Everything, a book he recalled from his youth). While it was rather different from the system in use today, it contained many of the same core ideas (and even some of the ideas of Berners-Lee's next project after the World Wide Web, the Semantic Web).

In March 1989, Berners-Lee wrote a proposal which referenced ENQUIRE and described a more elaborate information management system. With help from Robert Cailliau, he published a more formal proposal for the World Wide Web on November 12, 1990.

The proposal was modeled after EBT's (Electronic Book Technology, a spin-off from the Institute for Research in Information and Scholarship at Brown University) Dynatext SGML reader that CERN had licensed. The Dynatext system, however technically advanced (a key player in the extension of SGML ISO 8879:1986 to Hypermedia within HyTime) was considered too expensive and with an inappropriate licensing policy for general HEP (High Energy Physics) community use: a fee for each document and each time a document was charged.

A NeXTcube was used by Berners-Lee as the world's first Web server and also to write the first Web browser, WorldWideWeb, in 1990. By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web: the first Web browser (which was a Web editor as well), the first Web server, and the first Web pages which described the project itself.

On August 6, 1991, he posted a short summary of the World Wide Web project on the alt.hypertext newsgroup. This date also marked the debut of the Web as a publicly available service on the Internet. The first server outside of Europe was created at SLAC in December 1991.

The crucial underlying concept of hypertext originated with older projects from the 1960s, such as the Hypertext Editing System (HES) at Brown University, among others Ted Nelson and Andries van Dam, Ted Nelson's Project Xanadu and Douglas Engelbart's oN-Line System (NLS). Both Nelson and Engelbart were in turn inspired by Vannevar Bush's microfilm-based "memex," which was described in the 1945 essay "As We May Think".

Berners-Lee's breakthrough was to marry hypertext to the Internet. In his book Weaving The Web, he explains that he had repeatedly suggested that a marriage between the two technologies was possible to members of both technical communities, but when no one took up his invitation, he finally tackled the project himself. In the process, he developed a system of globally unique identifiers for resources on the Web and elsewhere: the Uniform Resource Identifier (url).