This book is, apparently, compiled from course materials for what must be a very fun class. It mostly covers two broad topics. First, producing unexpected sounds from radios and the circuit boards in toys, and modifying those devices in simple ways, such as adding photoresistors or new circuit board connections. Second, building simple synthesizers from scratch. The skills taught are basic, and form the building blocks for infinite exploration. The tools and parts needed are all inexpensive (often costing mere pennies). The included CD is great fun, but best saved for later listening, since it contains "spoilers" of what some of the projects might sound like.
Because of the book's origination in a class situation, the explanations and pictures are not always ideally clear. There are a lot of typos. However, the writing is so engaging and the book is so much fun that it still deserves 5 stars. Where the book is incomplete ("how to I de-solder something?"), the Web is there.
The book is clearly aimed at musicians without any electronics experience. Nonmusicians might still enjoy it, but a joy in playing with sound is absolutely required. I suspect the book would be way too basic for people with any significant experience in electronics.
As sidebars, the book includes a considerable amount of history of electronic music -- who's who and what they've been up to.