It talks about the language as an independent entity. It does not assume that you will have to write Java programs, etc. Furthermore, it does not assume that you know a lot about XML, and it does not want to tell you how the language is implemented. Instead, the book tells you how to use the basic features, and to understand how the output is created. With the information, you should be able to create any output you want, and not be surprised when an expected output shows up.
Some chapters are actually quite involved.
This is intended. From the experience I have helping web developers learn XSLT, there are a few concepts that are more difficult to grasp. I want the details of these concepts presented, and not swept under the carpet. Working with XML and HTML . It is also available in Barnes and Nobles , with a wrong name given, and Fatbrain .