Not too bad a book, but definitely an introductory text. It also has some curious gaps. For instance, it entirely omits Raytheon's VIGILANT EAGLE system for airport defense. It makes very little mention of contributions to DEW from the EW community. Other Active Denial System (ADS) it omits all energy-based non-lethal weapons. Finally, it makes very little mention of HPM-based EM threats. I expected it to at least survey the threats of EMP.
If you really want to learn about this subject, start with this book, and move on to your public library. Read the first few chapters of Jane's All The Worlds Fighting Ships and Jane's All The Worlds Fighting Aircraft for weapons systems principles. From there, move on to periodicals and read through the last fifteen years or so of Aviation Week's articles on EW/EMP/HPM. Finally, read the Executive Summary of the report by the EMP threat commission.