Preface

0.1. What This Book Covers

There are hundreds of formally established XML applications from the W3C and other standards bodies, such as OASIS and the Object Management Group. There are even more informal, unstandardized applications from individuals and corporations, such as Microsoft's Channel Definition Format and John Guajardo's Mind Reading Markup Language. This book cannot cover them all, any more than a book on Java could discuss every program that has ever been or might ever be written in Java. This book focuses primarily on XML itself. It covers the fundamental rules that all XML documents and authors must adhere to, whether a web designer uses SMIL to add animations to web pages or a C++ programmer uses SOAP to exchange serialized objects with a remote database.

This book also covers generic supporting technologies that have been layered on top of XML and are used across a wide range of XML applications. These technologies include:

All these technologies, whether defined in XML (XLinks, XSLT, Namespaces, Schemas, XHTML, and RDDL) or in another syntax (XPointers, XPath, SAX, and DOM), are used in many different XML applications.

This book does not specifically cover XML applications that are relevant to only some users of XML, such as:

Occasionally we use one or more of these applications in an example, but we do not cover all aspects of the relevant vocabulary in depth. While interesting and important, these applications (and hundreds more like them) are intended primarily for use with special software that knows their format intimately. For instance, most graphic designers do not work directly with SVG. Instead, they use their customary tools, such as Adobe Illustrator, to create SVG documents. They may not even know they're using XML.

This book focuses on standards that are relevant to almost all developers working with XML. We investigate XML technologies that span a wide range of XML applications, not those that are relevant only within a few restricted domains.