At first glance, Scott Seely's book looks like it might answer a lot of questions that a developer might have with regard to building SOAP applications. However, once inside I believe most readers will have a split experience. Scott hits the basics as most engineers would, but drills down directly into the minutiae without first setting up context for the reader.

To start with, the cover does a great job of attracting the reader by listing the key points that any developer would be interested in, such as multiple programming language support (C#, Visual Basic, C++, Perl, Java) and multi-platform support. Also, the bottom of the cover has some strong credentials for technical reviewers: Yves LaFon (Chair W3C SOAP Committee) and Kent Sharkey (.NET Frameworks Technical Evangelist, Microsoft).

Scott's first chapter gives a brief introduction to the history of distributed computing. Since Web services is based on a foundation of distributed computing technology it makes sense as to why Scott would include this chapter, but the treatment is empty and unrefined. The best part of this section is the coverage of Remote Procedure Mechanisms (RPC) and the problems with non-XML based RPCs.

At this point the book turns toward being really interesting and capturing the reader. Scott's coverage of SOAP basics acts to quickly inform the reader about XML and how it is used to build Web services applications. However, he does a poor job of explaining the different options that each of the SOAP elements has and what the impact of using them is. He covers the general options, for example 0 or 1, but does not drill down into what using 0 means and what using 1 means. This would have made this section of the book much more useful. It leaves the reader referring to the specification to figure it out.

The next few sections of the book concentrate on Scott's personal experience in building the SimpleSOAP library and have mostly code examples. I would have rather seen him use this section to talk about more of the complexities of implementing a SOAP library from the specification instead of focusing on the library specifics itself. This part ends with a lightweight treatment of UDDI and a discussion of available SOAP implementations, which because of delays in publishing was unfortunately out of date.

The final part of the book focuses on building a Web services auction system. Most of this code in this section is developed using a variety programming languages, such as Java, C++, Visual Basic and Perl. The upside to this is that the user gets to see the real power of Web services at work interoperating between multiple platforms and programming languages. The only downside of this is that it could make it difficult for those not well-versed in these programming languages to follow the example, which is critical to gain insight into really building a Web services application.

As I mentioned earlier, this book offers a mixed experience for the reader. Certainly the reader will learn something about building Web services applications and using SOAP. However, this is just a taste of the good stuff and the reader will need additional literature to support the more stringent details of application development or need to be able to read and understand the SOAP specification.

SOAP: Cross Platform Web Service Development Using XML
By Scott Seely
Prentice Hall PTR; ISBN: 0130907634

Reviewed by JP Morgenthal