PHP is hot, XML is hot, the combination of those two popular technologies seems to be the ultimate solution to
everything. But in which ways can PHP help you working with XML documents? This book tries to address this question by covering a lot of different standards related to XML. The book is fully buzzword compliant.

The first two chapters start by introducing PHP's basic syntax; operations, functions and classes are covered swiftly,
and XML. The XML introduction talks about what XML is, how it is originated and introduces the XML spefication, including DTDs and Schema's. The fourth chapter, 'Derivates', gives you an overview of the numerous different languages to represent data in XML documents. Per derivate it has info about its usage,
a small description, its links with PHP and mostly an example. This chapter gives a clear overview of the vastness of XML vocabularies.

The book continues by explaining the two major methods of processing XML: SAX (Simple Api for XML) and DOM (the
Document Object Model). These two methods are explained in great detail and are decorated with lots of examples with PHP. For both methods, a few interesting design techniques are covered which should give the reader a clear understanding of how SAX and DOM can be used, and when to choose which method. Next XPath, the XML standard for selecting nodes from an XML document and the XSL, the XML vocabulary for transforming
XML documents are dealt with. In chapter ten, all techniques and methods are
put together to show you the real power of XML and PHP. Then a few vocabularies
are covered, RSS and RDF for syndicating content from other sites, PHP as a client for web services by using WDDX and SOAP and XML-RPC to have PHP serve procedures to remote clients. These few chapters are very practical, but also have a good depth covering the vocabularies itself. The appendices cover some practical things for
working with PHP and XML: a reference for the PHP functions dealing with SAX, an appendix explaining the SAX API, the Document Object model and the XSLT and XPath references.

Professional PHP4 XML is a great resource for everyone wanting to use PHP together
with XML, it is a very practical book with lots of good examples, but the theory of all explained standards is of good quality and seldom boring. Readers will also be able to pick up some nice extra techniques, which can also be used outside XML in general, such as an introduction to OOP in the last appendice.