Forget the latest version by the same name. The book and that movie are not very closely aligned at all. Written in 1954 by Richard Matheson, I Am Legend is full of ideas that are considered common now, but were entirely unique when they first appeared. Robert Neville is the last remaining survivor of a disease that has destroyed humanity with symptoms resembling vampirism. The source is tied to a previous war, mosquitoes and the strange dust storms that came shortly after. He isn’t a scientist or genius. He’s just a man who had luck on his side and enough foresight to prepare once the world began to slip away. Through the book he faces the memories of what has come before and the bleak reality of what now is. It is less about the horror of vampires and more about the horror of utter loneliness that comes from being the last living man on the earth.
Difficulties with the book
The book is fairly slow in pacing. It takes a while tobuild up a sense of suspense for a reader already used to many of the hallmarks of what has become common horror tropes. If you have watched even a little bit of the horror movie genre or read many books, then the idea of being trapped in a house is old hack. There are moments when the pacing is quick and pulls you in, but the vast majority of the book sits in the range of introspective.
Positives the book has going for it
There is a strong focus on the effects of loneliness on the protagonist. Despite knowing that the vampires want to kill him, he shows at several points how they are a part of his only connection with other beings. How he changes through the book displays the harsh reality of a live lived for years alone. Perhaps the strongest positive to the book is how it has affected our current fiction. This book has been cited as inspiration for Night of the Living Dead for example. It was the first time that disease was shown as the source of a supernatural plague. The film adaptations may be lacking and almost unrelated to the original book in many ways, but there is no denying that the book has heavily influenced all sorts of horror that came after it. Resident Evil to Twilight all have elements that were first seen in this book.
Having never worked out a system for rating books, I choose to do as so many others have done before me. I will assign an arbitrary value and then explain why it isn’t as arbitrary as it seems. I am going to say 5 out of a possible 10. It is worth reading for the sake of knowing where many of our fiction concepts originated regarding vampires/zombies as a disease, but only once. It wasn’t a bad book, but it isn’t the sort of book you revisit and get something fresh from afterward. Read it, but try a library copy if you can find one unless you happen to catch it at a good price.