I bought and am enjoying this book on guitar and amp maintenance. The pictures are good, and the instructions and explanations are usually clear.
I bought this book to learn how to work on and repair both my axes and amps. I can honestly say that this shows you how hard it is to do! Not that it's the author's fault, but this is very tricky (and sometimes dangerous) to go at your guitars/amps with tools and hands.
I bought the book to learn how to bias my tube amp and I can honestly say, I'm not sure if I will do it! It is a complex procedure and will require an investment in some equipment (~$50-$200). The author smartly cautions against reckless tinkering with dangerous tube amps because of the risk of shock but I don't feel like he explained how to bias for a "regular joe". I mean, if you've got a bunch of high-tech equipment, the info is good. It's just not quite complete enough and clear enough for a beginner.
Also, sometimes the author has a brain fade. For example, he doesn't tell you where to find the bias control on your amp(!) or since that would be too hard to know without looking at your amp, what *location* it might reside in. He also doesn't tell you what objects in the amp to avoid (besides the filter capacitors) that could shock you after the amp is off.
If it's only the filter capacitors that can shock you with the power off, I would have enjoyed hearing that that was so! He does show you how to "drain" filter caps, which was great.
I would have liked to have heard that changing tubes is safe with the power off on a tube amp (and without draining the filter capacitors) but the book doesn't say. I wish he had discussed this.
A few small complaints: At some points during explanations of procedures, the author may "jump" a step and assume something that he hasn't previously explained. Sadly, these were omissions that simply slipped by both him and the proofreader. Lastly, the author spends a little too much time name-dropping. I worked with "Fred" or "Jimbo" or whomever in NY at such-and-such a store. Bottom line: if you're not one of these guys, who cares! Write them a postcard if you miss them!