Somewhat of a spoiler alert . . .
This was a very interesting take on vampires. It was interesting to see Matheson provide scientific explanations for vampires, specifically the spread of vampirism (how vampires turn others into vampires), weaknesses to garlic, mirrors, crosses, etc.
However, the character development of Robert Neville was by far the best part of the novel. His slow descent into madness and his struggle to remain in control of a world falling into chaos all around him was fascinating. The ending was a brilliant.
This novel isn't for everyone, however, but it's a quick read and certainly worth it.