"Programming Web Services in Perl" contains no instructions for installing Perl under Windows, no description of the CPAN network, and no short introduction to programming in Perl. The book is exactly what the title describes, programming Web Services using the Perl programming language. The authors are both closely involved with the design and development of Web Services and the related Perl modules, so the level of detail is very high. In fact, it makes for quite a dense read, but works well as a reference book.
The book starts with a couple of chapters describing the overall design and purpose of Web Services and a quick description of the XML and HTTP protocols that the services are based on. The remaining chapters jump straight in to writing code for the different toolkits that are available in Perl, starting with XML-RPC, through SOAP and WSDL to UDDI, REST and more advanced topics. Each topic is covered very thoroughly with lots of sample code. The book ends with five appendices containing Perl module references and the complete sample code used in the book. The examples cover both client and server side applications.
Each set of chapters creates a small example application to demonstrate how to use the toolkits. This also allows an interesting comparison in how the code can be clearer with the higher-level toolkits and more powerful. Running the code brings mixed results, some of the URLs seem to have changed since the book was written, but, hey, it is a good way to learn what is happening.
Although the book is aimed at Perl programmers interested in Web Services, some of the protocols are described clearly enough that the book may also be useful for programmers in other languages, such as PHP or C/C++. If you are such a Perl programmer then this book is "Highly Recommended", indeed, almost essential.