Undoubtedly, you've heard of Extensible Markup Language, commonly known as XML. You may have even seen some of it, though you might not have been aware of it at the time. One thing's fairly certain, however: You'll be seeing a lot more of it in the future.
My certainty is based on the fact that XML is beginning to spread at a pace that almost justifies the hype that accompanied its introduction, now that commercial vendors have discovered its potential. XML is showing up everywhere from configuration files to content management, from electronic data interchange to Web services to…well, you get the idea.
This book talks about all of these things, and does it in such a way that you'll be off and running pretty quickly, ready to start tackling your own projects. Before we get too far, though, let's talk about what XML actually is, so you'll have a feel for what you're doing here.