I Am Legend by Richard Matheson

Robert Neville lives from day to day trapped in his house. He spends the nights sleeping lightly, making sure the doors are all locked and that garlic is strung around all the windows and doors. If the days are cloudy enough, he doesn't venture outside either as they'll be out there. It's the strong sunlight that really gets them; but he'll work out a way to find more people like him - more humans, not vampires - and start over the human race. Robert is the sole survivor of a pandemic where the symptoms resemble vampirism.
One day, during his routine of hunting for supplies, he meets Ruth; a seemingly uninfected woman and takes her in. However, one night he wakes to find her gone and that she left a note confirming his worse fears.
As well as this story, this book has a collection of other shorter stories in it that are guaranteed to make the hairs on your neck stand up and make it hard to get to sleep. Yep, this is Stephen King country. For all fans of horror, you'll love this one.

Richard Matheson is the New York Times bestselling author of I Am Legend, Hell House, Somewhere in Time, The Incredible Shrinking Man, A Stir of Echoes, The Beardless Warriors, The Path, Seven Steps to Midnight, Now You See It . . . , and What Dreams May Come. A Grand Master of Horror and past winner of the Bram Stoker Award for Lifetime Achievement, he has also won the Edgar, the Hugo, the Spur, and the Writer's Guild awards. He lives in Calabasas, California.

(bibiography: http://search.barnesandnoble.com/I-Am-Legend/Richard-Matheson/e/9780312865047 )