The original invention document for the World Wide Web, March 1989, Tim Berners-Lee. He had already produced what turned out to be a precursor project called ENQUIRE whilst working at CERN for six months from June to December 1980.
Had an interesting enquiry from Sam:
I'm studying the history of the World Wide Web and most sources state that Tim Berners-Lee invented it alone, but some say he co-invented it with Robert Cailliau, a Belgian scientist. There is currently controversy about this on Wikipedia. do you know which is true?
Yes, Sam - I can safely say I do. Sir Tim Berners-Lee invented the World Wide Web in March 1989, when he submitted a proposal to his boss at CERN. Robert Cailliau became a highly valuble collaborator later. But the ideas and the invention and the writing of the first Web browser were all Tim's own work.
Robert Cailliau has never stated that he co-invented the Web. This inaccurate information has simply been parroted by certain Web users. In using the Web, one must be "information smart", and I don't recommend using Wikipedia for a start. It's an illogical nightmare of an idea, where uninformed, wishy-washy admins and silly, ignorant kids and adults can wreak havoc. Some people are so eager to thrust their own strange and inaccurate views on others they throw their rattles out of their prams and are amazingly persistent if challenged. Anybody trusting that source for a homework study deserves all they get! This is Tim Berners-Lee's own comment on Robert Cailliau's initial contribution to the project:
"Some commentators suggest that Robert co-invented the WWW. To set this straight, he did not invent it. It wasn't his idea. He did not write the specifications for UDIs (later to be URLs, then URIs), or for HTML, the hypertext language, nor HTTP, the protocol, or the code of the original implementation. More than a year after my original proposal (March 1989), while I was working on the code, he wrote a proposal to CERN proposing some staff be allocated to the project. This was a brave thing to do, as CERN was always chronically short of manpower for the huge challenges it had taken on. So Robert put himself out there to claim that effort on WWW was worth it."
https://www.w3.org/People/Berners-Lee/FAQ.html (scroll down to section "Robert Cailliau's Role" for further information)
And you can read our own piece on the wonderful Web here.
Sir Tim Berners-Lee celebrating twenty years since the invention of the Web in March 2009. The event took place at CERN.