The brief introduction of the book at the back says the below.
FreeBSD Unleashed includes complete coverage of everything you need to know to use freebsd to its fullest potential. It shows individuals how to exploit and put to use the same FreeBSD power that some of the worlds's largest internet sites have found so reliable. Whether you need an enterprise class server, a small business server, or a dependable workstation, this book provides powerful solutions to your most demanding needs.
This is a very good book. If you are a beginner and thinking of buying one book on freebsd this should be it.