With all the sophisticated tools available today such as OpenMP, this book may seem quaint. However before grasping at concepts or just using tools with out any understanding or their make up it would be wise to add this to your learning curve.
This book gives a good basic understanding of Pthreads. Of course you will later have to apply it to the real world but as a learning tool this is pretty darn good. The website or path on the sight has changed since publication; but the examples are still there. Because I am using AIX it does take a little time to convert from a gcc format to an AIX format. Then a little more time to apply AIX specific advantages.
As you go from the front of the book to the end the samples get added to and new concepts become available. There are plenty of diagrams for the visual learner. I personally found the signal handling of great use.
Any way this book is not the end-all, be-all, of threads but it sure cleared a lot of concepts up for me.