His writing style is okay, as far as putting one word in front of another goes, but he turns what could have been an action-packed thriller into a moderate-paced narrative.
The gist of it is someone has found a bundle of secret journals and letters by Lincoln, and gives them to a writer to make a novel from. That novel is the rest of the book. In which we learn how Honest Abe came to be a secret hunter of vampires, and how most of his family dies from vampirism. Seth re-invents vampires as super-human beings with super speed and strength. He gives them knife-like claws and psychic abilities. And the longer they exist, the less sensitive to sunlight they become, and most of the ones in the USA are able to co-exist with the living in daylight, with the help of sunglasses.
The author scrupulously follows real-life Lincoln's time line, but saves himself from having to write action scenes by skipping chunks of years with lame little notes about how Abe fought lots of vampires during those years, or retired from vampire hunting for those years.
Not a compelling book. Definitely not worth Kindle price. Pick it up at a used book store if you feel compelled to read it for yourself. I understand the movie hs gone way overboard on the blood and gore, so I'll be skipping that.