The DOM (Document Object Model) can be a clear and useful way to represent and interact with XML documents. It can also be a rather obtuse and un-obvious way to work with data when you first come in contact with it. In spite of some of its more difficult parts (especially as one digs into DOM Level 2 and 3) , the core DOM API is fairly consistent. It is this consistency that offers programmers some of DOM’s great strengths: operational sameness from language-to-language and system-to-system, schema-to-schema—and, to a lesser extent, browser to browser. As one works with it, however, one comes to realize that DOM is only a piece of a puzzle that fits into a greater whole in the XML world, and this consistency is only part of that larger philosophy that embodies XML.