As part of my research for the book series, I read through the entirety of the Report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack, as well as the shorter Executive Report. The manner in which an EMP works, what the after effects would be, as well as estimates on the casualties are all detailed in those two documents. Some time ago I placed both of these documents on my Research Downloads page for everyone to access.
I cannot stress this enough, you need to read these documents. Not everyone will fully understand all of it as they can be quite technical at times, but you should read them all the same. Readers need to make their own determinations as to how to they wanted to incorporate that knowledge into their daily lives.
That being said, it seems, that two of the reports' authors were recently on Capitol Hill to discuss the original assessment contained in the report and breathe new life into this potential cataclysmic problem given the rhetoric coming from North Korea. Here's the article that discusses their testimony and what we as a nation are potentially facing: Congress Receives Bone-Chilling Warning About the Results of a North Korean EMP Attack.
For additional information (Cliff Notes style), scroll down and read my post from August 13, 2017, A Note from the Author Regarding EMP. In that post I explain my need to include a disclaimer regarding the true effects of an EMP in Part IV of the series. After reading that, continue to scroll down to my March 6, 2017 post, EMP Related Information. In this post, I quite literally copied and pasted the text from Part III where I breakdown the science of exactly how an EMP works to shut down electrical devices, cars, the grid, etc.
The more information and knowledge you have, the better off you and your family will be.