This document discusses XML namespaces and how they allow elements and attributes from different sources to be combined without naming conflicts. A namespace is a set of unique names identified by a URI. The namespace is declared using the xmlns attribute and a prefix, and elements in that namespace are then identified using the prefix. Namespaces allow documents to be combined, reusable code modules to be invoked, and browsers to handle multiple sources of documents. Local and multiple namespaces are also described.