Heffelfinger has written an extensive user manual for NetBeans 6. That's what this book effectively is. The numerous screen captures and accompanying text walks you through the capabilities of NetBeans.
You can see how it uses windows of forms, where you type in various data, and it then makes HTML and XML markup based on that data. Far more robust than you manually writing markup, which is slower and highly error prone.
The text can also be used as a way to understand Java EE 5. This is more than just a way to write HTML. Using JSTL, it integrates to connecting to backend SQL databases. To this ends, NetBeans also is a top-down approach to generating SQL commands, which are then written as tags in markup. Useful if you only have a rudimentary knowledge of SQL. Similar to how NetBeans shields you from most HTML and XML.
Plus, NetBeans is also a front end to using java Servlets, JSP and JavaServer Faces. The first 2 have been around for several years and are quite mature. While JSF is newer, and is meant to be a standard web application framework, as an alternative to Struts or Spring. The book is an easy introduction to JSF, via NetBeans.
There is an awkwardness about many of the book's figures, however. The shading seems a little faded, and the contents of images inside the figures are not as crisply delineated as they could be. I think what happened is that screen captures were made of various NetBeans windows, converted to grayscale and then used as is. Perhaps some image enhancement steps could have been used to improve the renderings.