I picked up this book at Borders pretty much by chance. After thumbing through it I knew I had to own this book. It shows you how to setup your guitar so that it's running at 100%. If you need a simple repair, this book will show you how to do it. Interested in buying used gear? This book will show you what problems to avoid and which problems can be easily fixed.
For example, I didn't know that screwing down the tailpiece of my SG could collapse the bridge. This was a cause string buzz on my guitar.
initial guitar evaluation, fretboard cleaning and string installation, truss rod adjustment, nut adjustment and maintenance, bridges and tailpieces, whammy bars, bolt on necks, cleaning, intonation, and great setups.
This book concentrates mostly on the Les Paul and the Stratocaster. The author DOES discusses other hardware and how to care for it, but doesn't go into specific examples. Therefore, MOST of the detailed examples are for BOTH strats and Les Paul style guitars. If you have half a brain you can adapt though.
The other disadvantage is that SOME of the examples aren't detailed enough for complete tool novices. I guess if you've been repairing guitars for 20-30 years you take some knowledge for granted. Again, if you have half a brain or know someone who is good with tools, then you can figure it out.
Drawbacks aside, I HIGHLY recommend this book for anyone interested in caring for, buying, or playing guitars. You'll sound better for it.