The first 150 pages (one third) of this book have little to do with Java. Rather, it is a port of the authors' previous book on POSIX. It talks about three main platforms (Solaris, Digital, and Wintel) and goes into great detail as to how a Java VM uses each OS's primitives to offer Java synchronization. Why?
The authors show bias towards Solaris, and they spend a great amount of time focusing on how you can get the right number of LWPs on Solaris.
If I'm buying a Java book, I'm programming to the Java VM and could care less if Digital Unix gives you one light-weight process per CPU plus one for each outstanding system call. I also don't care about making native calls to the OS under Solaris.
The introduction suggests that multitheading offers increased speed by running on Parellel hardware. I think what people are really looking for is increased responsiveness. Most computers are single-CPU.
The authors are experts in their areas, and they do cover eventually cover multithreading in a no-nonsense manner, with the target audience being the advanced programmer. Don't be annoyed by thier constantly saying, "no, you don't want to do that. Don't do that", and then telling you why in a few more chapters.