BKTYXML2.RVW   20020212

"Teach Yourself XML in 21 Days", Devan Shepherd, 2001, 0-672-32093-2,
U$39.99/C$59.95/UK#28.99
%A   Devan Shepherd devan@architag.com
%C   201 W. 103rd Street, Indianapolis, IN   46290
%D   2001
%G   0-672-32093-2
%I   Macmillan Computer Publishing (MCP)
%O   U$39.99/C$59.95/UK#28.99 800-858-7674 317-573-2500 pr@mcp.com
%P   507 p.
%T   "Teach Yourself XML in 21 Days"

This book does have fairly complete coverage of XML (eXtensible Markup
Language), and all its related technologies, but one thing it does not
have is good explanations.  The examples are neither clear nor
complete.  It is just barely possible that you could teach yourself
XML with this text, but it would take considerable effort.

Part one is supposed to be about markup basics.  Chapter one is a poor
overview of markup languages.  While it does stress that XML is a meta
language, but it also confuses the function of XML with that of HTML
(HyperText Markup Language).  There is some review of XML syntax in
chapter two, but only in terms of filling in elements after they have
been defined.  Validity is explored, though neither clearly nor
convincingly, in chapter three.  Chapter four does explain DTDs
(Document Type Definitions) clearly and well.  The material is
frustrating, however, in that, of the examples given in earlier
chapters, primarily the third, and least interesting, example is
expanded.  The explanation of XDR (XML Data Reduced Schema), provided
in chapter five, is limited, questionable, sometimes contradictory,
and does not explain usage very well.  Chapter six's review of the XML
Schema Definition Language (XSD) has examples, but the exegesis is
almost incomprehensible, even if you know something of XML.  The
material on XML entities, in chapter seven, is easier but still
problematic: reordering the material might help significantly.

Part two starts to get into the processing of XML.  Chapter eight goes
to great lengths to explain why URIs (Uniform Resource Identifiers),
URNs (Universal Resource Names), and URLs (Universal Resource
Locators) are and should be unique, but fails to deal with how they
are used.  Diagrams showing how relative paths are like UNIX
directories still fail to demonstrate their employment in XML in
chapter nine.  There are confusing examples of Xlink and almost no
description of Xpointer in chapters ten and eleven.  Some references
to the Microsoft Document Object Model and a few JavaScript and
VBScript API commands (heavy on object addressing) take the place of
an outline of the XML Document Object Model in chapter twelve. 
Chapter thirteen uses lots of Java code, unexplained, in place of a
discussion of the Simple API for XML (SAX).  A determined reader with
a technical background and a lot of time for experimentation can
possibly figure out the basic use of Cascading Style Sheets (CSS) from
chapter fourteen.  This actually makes it one of the more promising
chapters in the text.

Part three purports to put XML to work.  Chapter fifteen, supposedly
telling us about the eXtensible Stylesheet Language (XSL) concentrates
on using the eXtensible Stylesheet Language for Formatting Objects
(XSL-FO) to process a data file into an Acrobat .PDF.  XSL
Transformations (XSLT) isn't explained in detail but chapter sixteen
does seem like another potentially useful section.  Chapter seventeen
discusses the binding of XML data to HTML elements, but does not
clearly explain which part of a complex process does what.  The Xbase
and Xinclude commands seem to merit their own chapter (eighteen), but
the text is confused about why this is so.  Chapters nineteen, twenty,
and twenty one are uncompelling sales jobs about the use of XML for
business, e-commerce, and the Web.

Much of the material reads like a rote regurgitation of phrases that
the author does not fully understand.  The book does not demonstrate
evidence of an informed overview of XML and a clear direction for
passing the concepts along to readers.

This volume does a very poor job of teaching, and, while it is fairly
complete in regard to the scope of XML (particularly those adjunct
technologies that Microsoft would like to have included), the text is
too limited to act as a useful resource.  Unfortunately, I fail to see
a particular audience that would benefit from this work.

copyright Robert M. Slade, 2002   BKTYXML2.RVW   20020212