I decided on a whim to read this and since it was so short I finished quickly in order to get back to the other books on my list, but I just wanted to give my thoughts on it since it did differ so much from what I was expecting.
The movie adaptation of this with Will Smith in it has always been one of my favorites, and having never read the book I expected it to follow pretty closely. I couldn't have been more wrong. The dog is only in the book for like two chapters! The ending is completely different too, and although I think Will Smith gave an excellent portrayal of living as who he thought was the last man on Earth, it wasn't a portrayal of THIS particular character.
I perceived from the movie that the creatures were zombies with more human intelligence than is normally seen in zombie movies, but in the book they are vampires. Full on vampires. Human intelligence just as they had when alive except on the crazy side of the spectrum.
I know I make it seem like I didn't like the story, but I really did. I thought the ending was even better than that of the movie and I wish someone would make an adaptation that really stuck to the book. It's not a happy ending by any means, but the revelation of it is thought provoking and makes you realize why the title is what it is.
It only takes a short time to read, so if you're a fan of the human psyche, apocalyptic tales, and vampires I think it's well worth your time.