Horror fiction is a genre of fiction in any medium intended to scare, unsettle, or horrify the audience. Historically, the cause of the "horror" experience has often been the intrusion of a supernatural element into everyday human experience. Since the 1960s, any work of fiction with a morbid, gruesome, surreal, or exceptionally suspenseful or frightening theme has come to be called "horror". Horror fiction often overlaps science fiction or fantasy, all three categories of which are sometimes placed under the umbrella classification speculative fiction.

Haunting is used as a plot device in horror fiction and paranormal-based fiction. Legends about haunted houses have long appeared in literature. For example, the Arabian Nights tale of "Ali the Cairene and the Haunted House in Baghdad" revolves around a house haunted by jinns. The influence of the Arabian Nights on modern horror fiction is certainly discernible in some of the work of H. P. Lovecraft.

Achievements in horror fiction are recognized by numerous awards. The Horror Writer's Association presents the Bram Stoker Awards for Superior Achievement, named in honor of Bram Stoker, author of the seminal horror work, Dracula. The International Horror Guild presents its own annual awards, as do organisations such as the Australian Horror Writers Association with its annual Shadows Award. Other important awards for horror literature are as subcategories included within general awards for fantasy and science fiction in such awards as the Aurealis Award and the British Fantasy Award.

Today horror is one of the most popular categories of film.
Crime fiction is the genre of fiction that deals with crimes, their detection, criminals and their motives. It is usually distinguished from mainstream fiction and other genres such as science fiction or historical fiction, but boundaries can be, and indeed are, blurred. It has several sub-genres, including detective fiction (including the whodunnit), legal thriller, courtroom drama and hard-boiled fiction.
While the archetype for a murder mystery dates back to the "The Three Apples" in the One Thousand and One Nights, crime fiction began to be considered as a serious genre only around 1900. The earliest known crime novel is "The Rector of Veilbye" by the Danish author Steen Steensen Blicher, published in 1829. Yet more known are the earlier dark works of Edgar Allan Poe (e.g., "The Murders in the Rue Morgue" (1841), "The Mystery of Marie Roget" (1842), and "The Purloined Letter" (1844). The evolution of locked room mysteries was one of the landmarks in the history of crime fiction. The Sherlock Holmes mysteries, probably based upon C. Auguste Dupin and Émile Gaboriau's Monsieur Lecoq, are said to have been singularly responsible for the huge popularity in this genre. A precursor was Paul Féval, whose series Les Habits Noirs (1862-67) feature Scotland Yard detectives and criminal conspiracies.

The evolution of the print mass media in the United Kingdom and the United States in the latter half of the 19th century was crucial in popularising crime fiction and related genres. Literary 'variety' magazines like Strand, McClure's, and Harper's quickly became central to the overall structure and function of popular fiction in society, providing a mass-produced medium that offered cheap, illustrated publications that were essentially disposable.

Like the works of many other important fiction writers of his day — e.g. Wilkie Collins and Charles Dickens — Arthur Conan Doyle's Sherlock Holmes stories first appeared in serial form in the monthly Strand magazine in the United Kingdom. The series quickly attracted a wide and passionate following on both sides of the Atlantic, and when Doyle killed off Holmes in The Final Problem, the public outcry was so great, and the publishing offers for more stories so attractive, that he was reluctantly forced to resurrect him.

Later a set of stereotypic formulae began to appear to cater to various tastes.