XPointer is the social fragment identifier for XML documents. Using XPointer, it is possible not only to link complete resources but also to create links between parts of resources. XPointer is built on top of XPath, and it extends XPath's model with some new concepts. This chapter describes XPointer in detail and demonstrates to readers how to create their own XPointers. These XPointers may then be used in links, which are described in the following chapter.