The books are EXCELLENT, and better than the TV show (which I also like a lot).
https://www.amazon.com/gp/bookseries/B00K7B2CRQ
There are 9 books total, not including the novellas. The last book of the series is scheduled for later this year.
It's structured as 3 trilogies. The tone and pace of the first book is maintained (for the most part) through the entire series. So, if you like the first book, you'll probably like the entire thing.