No, I have not read the books. In fact, this is the first I’ve learned of books.
http://www.randomhouse.com/doubleday/dexter/aboutbooks.html
But the show departs from them early on. So in a way they are an “alternate universe”. Still well written though.
Got the first three as Christmas presents last year from MIL.
Hubby wasn’t happy that his mom bought me books about a serial killer for CHRISTmas. lol.