This book is targeted at programmers who need todevelop solutions using XML. Being a programmer myself, I know that theory without practical examples andapplications can be tedious, and you probably want to getstraight to real-world examples. You’re in luck, because thisbook is full of working examples — but not in this chapter.Some theory is necessary so that you have a fundamentalunderstanding of XML. I’ll keep the theory of XML and relatedtechnologies to a minimum as I progress through the chap-ters, but we do need to cover some of the basics up front. This chapter provides readers who are new to XML with anoverview and history of XML, its purposes, and comparisonsagainst previous and alternative integration technologies, andends with an overview of the next XML version, XML 1.1. Therest of the chapters in this part of the book will use real-worldexamples to describe XML basic formats, the structure of well-formed XML documents, and XML validation against DTDs andSchemas. The chapters on XSL Transformations and XSLFormatting Objects will illustrate the transformation and for-matting of XML data using XSLT via working examples. Thispart of the book will be finished with examples of parsing XMLdocuments, as well as specific examples of XML parsing usingSimple API for XML (SAX) and Document Object Model (DOM).