I picked up this book on impulse the other day, when I saw it at Barnes & Noble: Stable Smarts, by Heather Smith Thomas.
The book is a really useful collection of all kinds of horse advice, from building fences and taking care of leather, to treating wounds and warding away flies. Honestly, of all the horse books I owned and have read, this one is probably the only one that was actually worth spending the money on. I'm even considering buying another one to keep at the barn — they ought to make a really durable (i.e. spiral bound and laminated covers) edition just for that purpose, since at the barn is where most people's copies will probably be kept!
Please also check out the more in-depth review of this book on my horse blog!