SynopsisXML has spread rapidly into all aspects of computing because of its radical flexibility. Developers can create vocabularies that identify data and document structures according to their own preferences. While this flexibility is powerful, it has also driven the development of vocabularies that describe and constrain those structures, called schemas. Unfortunately, developers have been trapped between relatively weak but easily approachable XML 1.0 DTDs and the much more powerful but dauntingly complex W3C XML Schema. Over the past few years, an alternative has emerged, combining the ease of DTDs with the power of W3C XML Schema: RELAX NG.This book explores this new schema vocabulary, from its clean foundations through best practices to integration with other data-description approaches. While working with RELAX NG is easy compared to W3C XML Schema, there is still plenty to learn. RELAX NG explains both the XML syntax and compact syntax in depth, showing how to use every pattern in both syntaxes with clear, simple examples. Whether you're a programmer defining XML vocabularies for interchange or a document manager supporting new metadata in a publishing environment, you'll find RELAX NG a refreshing approach to describing XML. This book provides a complete guide to this exciting new technology, from how to get started to how best to apply it to many different kinds of XML problems.