Tor Books I AM LEGEND

Robert Neville is the last living man on earth ...but he is not alone. Every other man, woman and child on the planet has become a vampire, and they are all hungry for Neville's blood. By day he is the hunter, stalking the sleeping undead through the abandoned ruins of civilization.§§By night, he barricades himself in his home and prays for the dawn. How long can one man survive like this?