"For most of this book, my examples are going to focus on XML protocols. These are XML applications used for machine-to-machine exchange of information exchange across the Internet over HTTP. In this chapter I'll show you how such documents move from one machine to another... However, since this is not a book about network programming, I'm going to be careful to keep all the details of network transport separate from the generation and processing of XML documents. When you work with an XML document, you don't care whether it came from a file, a network socket, a string, or something else."