What can one say about a Tax Guide? If you know your way around taxes this won't help you much, but there are a few gems in there for those who are only partially aware of the Tax laws.
I'd say if you've never read one of these then you really ought to do so. The cost is little and the time it takes will be less than you expect. All you need to do is find one thing that you can use and it will have paid for itself many times over and you can bore all your friends with your new-found knowledge of tax avoidance (avoidance is ok, evasion is not!). Even if you don't find anything to increase your wealth you will know this for sure and will probably sleep better knowing the taxman is taking only what is due.
This is the first tax guide I have read, and I found it easy to follow, with examples helping explain things. Competitor guides may be worth looking at to ensure you're getting full information once you've pinned down whatever it is you need to learn more about. A worthy read.