Learning XML, 2nd Ed., by Erik T. Ray ISBN 0-596-00420-6

Reviewed by: Songmuh Jong, send e-mail Published by: O’Reilly and Associates, Inc., go to the web site Requires: Some knowledge of HTML and web concepts MSRP: $39.95 eXtensible Markup Language (XML) has rapidly achieved high acceptance in information technology. Most new software projects are using XML to one extent or another. Almost every field, discipline or application has developed its own XML tag library and the number is increasing. For developers, there is a need for a one-stop resource for XML. The scope and coverage of this book is very extensive and is sufficient for both beginners and experienced developers who want an introduction to this area. There have been numerous good reviews published for this book and the general opinion is that this is an excellent book. This review fully agrees with them. But this review will skip most of the praises and take a more critical angle in an attempt to help readers understand what they can get out of the book. This book is divided into 10 chapters with two appendices. The topics fall into either the data description (markup) using XML, or the data presentation out of an XML document. Chapter 1 gives an overview of the XML topics and provides a surprisingly large number of examples to illustrate each topic. This is one of the rare books that, after reading chapter 1, readers may feel that the topics are so broad they won't be fully explained later in the book. It's also a rare uncertainty from chapter 1 that readers may not clearly understand what tools the author uses for XML editing and processing. It appears variously that the author uses everything or may only be simply using Perl and Internet Explorer. Chapter 2 describes elements in an XML document. Chapter 3 gives several examples of XML documents and a few access methods. Chapter 4 is about XML document validations using DTD or schemas. Chapters 5 to 9 are about XML presentation. Since there is a chapter devoted to XSL-FO, it is disappointing that the book doesn't also discuss PDF transformation. It is also surprising that no example is given for the chapter on Internationalization. In view of the recent advances in the .NET technology and its built-in XML functionality, it would have been useful if the book can included a contextual discussion of that topic. Chapter 10 finalizes the discussion of methods and tools repeatedly mentioned in earlier chapters to parse the XML documents.

This books reminds me of a type of short course, often found at the University level, in which students watch in awe as the lecturer goes through each topic quickly and expects a lot of homework to be done afterwards. There are many questions forming in their minds, yet there is no time to raise the questions.

It is interesting to read the occasional discussion of history such as the origin of XSLT and the related W3C XSL-FO project. It is also nice that all the examples can be downloaded from the book web site. Chapter 2 Markup and Core Concepts can be freely downloaded from the same site. It would have been helpful if the book had organized its references at the end of each chapter. Citing references within text can sometimes be hard to locate afterwards. Although there is an Appendix A for resources, it doesn't include all the references in the book. For a technical book like this, it'd be helpful if the author detailed the requirements for tools such as the Perl packages and Java libraries. Instead of simply presenting the starting XML document and the final transformed document, it's generally more useful and instructive to show the tool and syntax used when running the transformation program.

Learning XML is an excellent reference and can serve as an instructor-guided textbook for an introductory XML course. It also makes a good self-study book for XML enthusiasts.

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