There are a lot of books out that use EMP as the focus of their plot.
The two that have garnered the most attention are Lights Out and One Second After.
Lights Out started as a serial novel, available free on the internet. Crawford would write a bit, then there would be an interval, then he would write some more. The number of people reading his story grew by leaps and bounds, and eventually a publisher put out a hard copy version. I've read it twice. It's typical of early post apocalyptic literature, in that it could have used some decent editing. The conversation is often a bit stilted, and it isn't as smoothly flowing as most hard copy books produced by a publisher (as opposed to self published.) However, it's an interesting book and there's a lot of hard, actionable information in it. If I had any particular facet that I'd say irritated me, it was the painfully obvious attempt to be politically correct. But I suppose you can't avoid that these days.
One Second After also deals with an EMP "Black Swan" event. It was written by a college professor , and takes place just north of where I am located. It's a well written book, very smooth and flowing in the story line. The characters are believable, and the story will make you think about some issues you may not have considered prior to reading it.
However, fairly or unfairly, much of the plot has been alleged by detractors to be derivative of Lucifer's Hammer. There is a similarity in some aspects of the two novels, but I think that's more to do with the fact that events as detailed in both books are logical. That just means that both authors see certain possibilities to be likely after a catastrophic event, not necessarily that one copied the other.
They're both worth reading if you are interested in EMP.