If you've ever thought it would be cool to build you own gear but just didn't know where to start, here's where. This is without a doubt the best DIY book I've seen. Don't let the title fool you, this book is not just for guitarist, all electronic musicians will find lots of things to like here.
Liberal illustrations link real parts to symbols and connections between parts to schematics.
The project on designing a preamp is my favorite. It goes through the thought processes and decisions made while designing an actual circuit. Something the DIY hobbyist has needed for a long time, and all with only the barest hint of math. It's pretty hard to imagine adding anything to Craig's classic Electronic Projects for Musicians . But fortunately you don't have to, Projects for Guitarists does it.