Man is a Social Creature
The pervasive tone of the novel is one of the loneliness that would come with being the last person on earth. Of course, technically, the book’s protagonist is the not really the last person on earth and therein lies the conflict of this theme. The almost-but-not-quite human companions at the end of the world with Robert Neville are “almost” enough to reveal the desperation that comes with the loss of human contact: “...the women who made it so difficult, be thought, the women posing like lewd puppets in the night on the possibility that he’d see them and decide to come out.”
McCarthyism
Like another popular hybridization of science fiction and horror from the 1950’s—Invasion of the Body Snatchers—the novel exploits what had been double-edged sword of such genres not receiving much critical respect at the time to do what mainstream films and novels had a time doing: making social commentary on the effects of McCarthyism and actual fear of communist subversion. When Neville learns the full truth about exactly how not alone he really has been, it is much like the moment when the hero and girlfriend in Body Snatchers peer down at the town square and realize everyone has become replaced by the mindless pod substitutes. Neville’s unspoken recognition could just as easily have been voiced at the moment in the movie: “Normalcy was a majority concept, the standard of many and not the standard of just one man.” Normalcy, in other words, is simply conformity and the fear of conforming to a standard with they disagreed is the one thing McCarthyites and their blacklisted victims shared. Of course, the anti-McCarthyites were the only ones who actually did become victims which is why Matheson hid his critique within what appeared to be just a story about vampires.
Science Displacing Superstition
The “vampires” in the book are not vampires in the traditional sense and that is part of the point. They actually much more in common with the 21st century concept of zombies as infected beings rather than the living dead or the dead risen back to life. The book’s hero tries to understand the vampires from historical perspective only to wind up realizing they are the result of a genetic mutation. So the narrative exists to start the process of transforming vampire as a being connected to myth, superstition and religion and into a 20th century scientific anomaly which can be studied and, perhaps, even cured.
