The XSL Transformations (XSLT) specification defines an XML-based language for expressing transformation rules that map one XML document to another. XSLT has many of the constructs found in traditional programming languages, including variables, functions, iteration, and conditional statements. In this article you'll learn how to use the XSLT instructions and template rules, manage namespaces, control transformation output, use multiple stylesheets, and employ pattern-matching with template rules. A sidebar explains how to access XSLT from MSXML using the IXSLTemplate and IXSLProcessor interfaces.