Fantasy is a genre that uses magic and other supernatural forms as a primary element of plot, theme, and/or setting. Fantasy is generally distinguished from Science fiction and Horror by the expectation that it steers clear of technological and macabre themes, respectively, though there is a great deal of overlap between the three (collectively known as speculative fiction).
In popular culture, the genre of fantasy is dominated by its Medieval form, especially since the worldwide success of The Lord of the Rings books. In its broadest sense however, fantasy comprises works by many writers, artists, filmmakers, and musicians, from ancient myths and legends to many recent works embraced by a wide audience today.
It is difficult to define the precise 'beginning' of fantasy literature, as stories involving magic, paranormal magic and terrible monsters have existed in spoken forms before the advent of printed literature. Homer's Odyssey thus satisfies the definition of the fantasy genre with its magic, gods, heroes, adventures and monsters. Fantasy literature, as a distinct type, began to become visible in the Victorian times, with the works of writers such as William Morris, Lord Dunsany, and George MacDonald.
J. R. R. Tolkien played a large role in the popularization of the fantasy genre with his hugely successful publications – The Hobbit, and The Lord of the Rings. Tolkien was largely informed by an ancient body of Anglo-Saxon myths — particularly Beowulf — as well as modern works such as The Worm Ouroboros by E. R. Eddison, and it was after his work that the genre began to receive the moniker, "fantasy" (often applied retro-actively to the works of Eddison, Carroll, Howard, et al.). J. R. R. Tolkien's close friend C. S. Lewis, author of the The Chronicles of Narnia, also an English professor interested in similar themes, was also associated with popularizing the fantasy genre.
A large proportion of fantasy books are in a medieval setting - Tales of Redwall, The Lord of the Rings and The Chronicles of Narnia are all medieval fantasy books.
See Fantasy for a list of Fantasy books.