(Please add this book to the "Official ATT Painting Resource" thread.)
Link to buy: http://www.forgeworld.co.uk/Modelling-S ... E-ONE.html
(Should also be available on the main GW website, but their IA section is currently missing.)
I've been using this book for a while, and I just realized that there doesn't seem to be any information about it on ATT. Which is sad, because it is probably the single most useful thing you can buy if you care at all about the quality if your models*. For a mere $40 you get:
1) Step by step guides for everything, from basic assembly all the way through weathering and diorama displays. Obviously the tips on getting a good base/color coat are useful, but where it really helps is in weathering. You get full, detailed explanations (with pictures for every step) of pretty much every kind of weathering you can imagine: paint chips, dust/dirt, oil stains, rust, etc, it's all there. And most** of these techniques are things even an average painter can use. You might not realize it now, but simply following the basic directions and adding some weathering can turn a boring tank into something that will win painting contests.
2) Large, full-color photographs of various models, including closeup shots and explanations for the most interesting parts and techniques. Once you've got the basic concept from the step by step directions, you can look at a nice supply of ideas for how to apply them. And fortunately for us, there are two Tau models included: the Tigershark AX-1-0 and the Barracuda. In my opinion, they are excellent examples of how even the "clean" Tau models can benefit from some subtle weathering.
And the really nice part about it: you know how every GW guide is full of "use the Citadel Mixing Pot (link to buy) to thin your Citadel Colour Paints (link to buy) with official Citadel Water (link to buy) Citadel Spray Gun (link to buy), and you will experience the satisfaction of being part of the Games Workshop Hobby (tm). Be sure to buy a Baneblade (tm) (link to buy) and some Space Marines (tm) (link to buy)"? There's none of that garbage in this book. Obviously they use GW paints, but if there's a non-GW tool that's right for the job, Forge World is not afraid to suggest it.
In short: this is an amazingly useful book. Unless you just don't care at all about painting, skip buying a crisis suit or two and get a copy.
*Unless you're one of those people who's already an expert at painting, and even then it's still worth it for the pretty pictures.
**Some things do require an airbrush, but even without one you can still do enough to produce some very impressive results.