In the book I look at user interfaces quite a bit. Chapter 2 is an overview of the GWT user interface library. There is a section on cascading style sheets, an easy declaritive way to add styles to your user interface, in chapter 5. Chapters 6-10 illustrate construction of 5 different applications using MVC architecture and a detailed look at each application's view. In other words you'll get an overview to get you started and plenty of detailed examples to pick up tips and techniques.
Since you're coming from building server side applications (me too!) you'll find yourself very comfortable with the GWT way of doing things. GWT abstracts many browser technologies with
Java so you can use solid software design techniques. You'll notice many GOF design
patterns in the toolkit including Abstract Factory Pattern and Observer Pattern. You'll be able to do performance
testing and unit testing. Also your user interface will compile down to be more efficient JavaScript than if you had coded the application by hand.
Let me know if you have more questions about using GWT for your interface. I could go on and on about how its a great tool. As for whether the book is for you to learn user interfaces, if you've been convinced GWT is the way to go, which I believe it is in many cases, then I think you'll find the book a great way to get started and get in depth.
[ November 13, 2007: Message edited by: Ryan Dewsbury ]