Sams Teach Yourself XSLT in 21 Days covers XSLT and Xpath (as a part of XSLT), as these topics have everything to do with processing XML. It also covers XML from an XSLT processing and design point-of-view. Other XML technologies will not be discussed, most notably XSL, as superset of XSLT. XSL Formatting Objects alone form enough material for an entire book. Apart from that XSLT and Xpath form the processing/programming section of the entire XSL specification.