W3C sums it all up
The document, entitled Architecture of the World Wide Web, Volume One is meant to provide the definitive reference to how the Web works. While most of the information contained in it is well known, it's never before been gathered together in one place.
The Technical Architecture Group (TAG) of the W3C produced the document in response to numerous requests from various members of the Web community. The TAG was first set up in 2001 to oversee the development of Web architecture, with particular responsibility to document the architecture and resolve any issues with standards. Since then it's had its charter updated as the Web has developed, with the latest version being published in October of this year.
"All TAG participants, past and present, have had a hand in many parts of the design of the Web," said Tim Berners-Lee, W3C director, and co-chair of the TAG. "In the Architecture document, they emphasize what characteristics of the Web must be preserved when inventing new technology. They notice where the current systems don't work well, and as a result show weakness. This document is a pithy summary of the wisdom of the community." The group hopes the document will help developers make the best use of Web technologies, and to gain the benefit of other users' experience. "The discussion process produced a wider appreciation of the design principles on which the Web is based," said Chris Lilley, TAG participant, "and the Architecture document crystallizes that shared understanding for easy reference."
The two main subjects covered by the document are URIs and XML. The former's role as the Web's addressing and identification mechanism is discussed, while the latter's place as the Web's universal language is also covered. Architecture of the WWW itself is by design a high-level document, but still covers many technical details of the architecture. Its status within the W3C is "Recommendation", the highest level of standard the consortium has.
The process of writing the document was backed up by public consultation via a mailing list to ensure that the views of people working with Web technologies was taken into account, not just those of software vendors or academics.
As 'Volume One' in the title implies, W3C plans to produce more publications on the Web's architecture as it evolves. Subjects to be covered in the future include the semantic Web, mobile Web use and Web services.