The author starts out trying to explain Java3D. His explanations are OK, but the best explanation I have ever found as an overview of the API is "Java 3D API Tutorial" on the Sun Microsystems website.
It's old, but the basics haven't changed. For the specifics of working with Java 3D in the modern era, come back to this book.
The author has done a good job of putting together some programming examples that show how to program in current versions of Java 3D including a 3D version of Conway's game of life.
