The horror-and-suspense genre was one of the most popular during the peak of radio's reign in the early twentieth century. The genre was successfully transported to television in the early days of the medium. The focus of horror and suspense is fear, and these programs try to make the viewer uneasy or afraid in an entertaining way. Programs in the genre usually include elements of the supernatural, but these elements are not necessarily a requirement.
The distinction between horror and suspense lies in the specific type of uneasiness that the story tries to provoke. Horror aims for a visceral kind of fear, often rooted in revulsion, and horror programs are likely to include violence and situations that cause strong emotional reactions in the viewer. Suspense is more subtle; it tries to evoke a feeling of dread, and it relies more on the anticipation of something bad happening than it does on the actual unpleasant event itself.
Early TV suspense programs were much like radio suspense programs in that each episode featured a unique, stand-alone story that was not related to the stories in other episodes. Series such as The Twilight Zone and Outer Limits presented stories that drew on other genres-crime, science fiction, horror-and were characterized by suspenseful plots that typically built toward a surprising twist at the end.
Horror and suspense was largely absent from television through the last couple of decades of the twentieth century, but the turn of the century saw the development of some new forms. The horror drama fused the supernatural with genres such as action and adventure-the monsters and demons of Buffy the Vampire Slayer are a good example-and more recent dramas introduce zombies and vampires into typical action- and romantic-drama situations.