XML did not originate in a vacuum. It built on the successes and lessons learned from SGML and in that respect was a mature technology from the start. The stated goals of XML articulate an entire business case for structured electronic information. They also spell out warnings of how an XML strategy could go wrong. Our association of XML with the Web is no accident. The Web has been a driving force in the development of XML from the start. In turn XML is a strong determinant in the development of Web browser technologies. XML for agile and portable content and XML for the Web is now an established fact. Whereas HTML is an adequate vehicle for delivering Web pages, XML is a robust technology for total content definition and management.