XML makes it possible to store content in a standardized format that can be converted to a variety of output media using a broad choice of technologies. Most of these technologies build on related W3C standards with both commercial and open source tools support. XSLT lets you define a transformation of a set of documents into a particular format, so that three XSLT stylesheets could create published products from the same content for three different media. The XQuery language lets you pull subsets of XML content from huge repositories, so that XML databases that support XQuery can (among other things) provide dynamic publications customized for different customers.
If you are looking for introductory material on XSLT and XQuery, you should try the "Hands-on Introduction to XML" course. Intermediate XSLT developers looking for more hands-on material should consider the Hands-on Digital Publishing With XSLT course. Classes in this course are more advanced and focus on helping XSLT and/or XQuery developers with more experience get the most out of their code and their development time.
Classes for 2018
The XSLT and XQuery course runs on and .