XML has firmly established itself as the universal standard for managing data for the web and is now being implemented on a wide scale.
XSL (eXtensible Stylesheet Language), a vital companion to XML, is used for two main purposes: to format or style XML data so that it can be displayed in a browser and to transform XML data (XSLT). When you transform an XML document, you manipulate the data into a new structure, for example, re-ordering the data. This enables the same data store to be used in an unlimited number of ways. XSLT is a flexible, customizable, and cross-platform language.
XSLT is a notoriously difficult language to understand, but this book, while being a complete reference to the recommendation, will also give code examples showing how it all ties together and can be effectively employed in a real-world development scenario.