Quite simply the best technical book I have read in 20 years. It goes through each step setting up complex tasks such as failover with CARP and setting up VPNs. It goes into every possibly option in detail, and includes comprehensive trouble shooting steps. This book made fixing a faulty failover setup a breeze. If you use pfsense, you should have this book. We have this book in the office, but I had to buy myself another copy for home. It is aimed towards the lay admin - you dont have to be a networking or firewall guru to use it. I learnt a lot about networking concepts in general from this book too (eg about bridging loops & outbound NAT).
Essentially all the information in this book may be got online from the pfSense.org site but if like me you like reading a proper book then it's all here, and very clearly laid out with good bold headings. The edition supplied is dated October 2009 so a little out of date but you can always refer to the web site, I am in the process of deploying the embedded version using the FreeBSD methodology called "nanoBSD" where the whole operating system is loaded from a read only Compact Flash at boot into RAM and uses only virtual RAM disks in operation so avoiding wear to the card. Can't really add more at present , I am trying to get to grips with the concepts of Virtual LAN's which the book seems to describe very well with actual configuration examples of currently available switches i.e. Netgear GS108T which luckily I had obtained a pair of in intending to upgrade my network to Gigabit before learning of pfSense.
Very clear and well written. If you are going to deploy pfSense in your home or office get this book, there are features in it I hadn't realized. This isn't a dummy's guide to the internet and nor should it be, you need to at least have a basic understanding of IP addressing and ports.
This is an exceptionally useful and thorough book and I don't believe I would have had the confidence to use pfSense without it.
NB If you look on the US Amazon site (substitute .com for .co.uk in the address bar, leaving the rest unchanged) you'll find a lot more reviews (18 at the time of writing), almost all with 5-star ratings, and there is nothing helpful I can add to these.